This trope is about characters who, for various reasons, don't have time for the usual grooming rituals or to keep their personal space tidy. It can be a one time thing (to show a given character is under pressure or has become obsessed with something) or part of their normal characterisation. Either way, they have something other than their appearance on their mind.
The reasons for this can be external; events out of the character's control are keeping them from a nice warm shower. Or they can be internal; the person in question has let their appearance slide because they're more interested in what they're doing. The former can either emphasise the significance of what they're doing (i.e. their job's hard) or suggest that the character's having difficulty dealing with it (i.e. they're bad at their job). The latter tends to simply mark the character out as devoted to their job (or whatever it is they're doing) and is far more likely to be Played for Laughs. Although it can still be Played for Drama, especially when it's motivated by guilt.
Characters who frequently show this trait include the Defective Detective (and their more well adjusted colleagues when the situation's really serious), the Salaryman/White Collar Worker (especially if they're a Beleaguered Bureaucrat), The Atoner, Workaholics and the Absent-Minded Professor. The Panicky Expectant Father is an example of the "one time" variation (although looking after their new offspring might make the trope stick). It can also be a sign of a Bunny-Ears Lawyer, Sanity Slippage, Villainous Breakdown and the reason somebody's a Genius Slob. Someone who Must Have Caffeine will often display this trope with or without the two being connected (in the former case, it might be cleared up after they've had their fix). Plot-Powered Stamina tends to have this as a side effect when it's being played more realistically.
This is, obviously, Truth in Television; Your personal appearance needs daily maintenance (clean clothes, washing, combing hair, shaving, etc.), so it's usually the first thing to slip when someone's pressed for time.
Supertrope to Messy Hair and Einstein Hair (which specifically marks someone as a Mad Scientist). Compare Fashionable Asymmetry and Rummage Sale Reject for other wardrobe problems, Beard of Sorrow and Mess of Woe for depression induced deterioration and Forgets to Eat. Contrast The Pigpen (who's a mess because they're lazy rather than busy) and the more positive Adrenaline Makeover.
- As 7 Seeds takes place After the End and personal grooming is not an urgent priority to them, majority of the characters will end up looking scruffy as things go along. The biggest, visual examples are Hana, whose long hair becomes so unkempt, entangled and split-ended, she ends up cutting it short. Aramaki, whose short hair grows down to his waist during the 15 years he's spent wandering the earth alone, including a pretty impressive beard that he eventually shaves off. And Tsunomata, who later appears with long stubbles in his face, though he shaves the stubble away to keep behind a scruffy, sort-of beard around his jawline.
- L from Death Note is a genius detective who rarely seems to even sleep (let alone do something about his hair or put on something other than a baggy white shirt and trousers) when he's working on a case.
- Elfen Lied's resident Hot Scientist Dr. Arakawa is working so hard that she never has time to take a shower. Becomes a Running Gag in a show that desperately needs them.
- Ghost in the Shell: Stand Alone Complex often shows this trope when the team are burning the midnight oil (along with many empty or half empty boxes of pizza and cigarette stubs). Mainly Ishikawa (and whoever ends up helping him), since he does most of the research related work. Togusa also falls into this when he's investigating the death of a former colleague in "Interceptor".
- Skip Beat! has this occur with Erika Koenji during her second appearance. She has been in an accident and, due to psychological trauma, unable to move her legs anymore and is bound to a wheelchair. She's still festering about the accident, leaving her hair disheveled and generally ignores her appearance, which she usually keeps pristine.
- Inverted by Dr. Stein in Soul Eater. When his appearance is going downhill, it's usually a sign he's in no fit state to work. In the anime, after the Kisin is released, Soul drags Maka away from her studies to play basketball in order to avert this trope.
- Cher from Wolf's Rain usually looks like this whenever she's engrossed in her work, which was often enough that her marriage ended in part because of it.
- Discussed in Spider-Man; Aunt May remarks that Peter is so busy that he often leaves his room untidy.
- The "Work" edition of the Worst Case Scenario Handbook series of Faux To Guides suggests invoking this (messing up your hair and clothes) as a tactic to avoid being made redundant.
- Combined with Mess of Woe in The Count of Monte Cristo when Villefort works several days nonstop to keep his mind off the death of his in-laws and his daughter, looking dishevelled and unshaved (though he shapes up in time for the trial).
- The Discworld's unshaven and scruffy cop Samuel Vimes prefers to conform to this trope, although his wife is quite insistent that he maintain appearances after he marries her. One of his monologues even notes his disgust at a palace guard's sword, since it didn't show any nicks and dents and clearly never saw any use (as opposed to a well maintained sword which still showed wear and tear).
- Alan Grant is like this in Jurassic Park as a way of showing himself as a rugged outdoorsman and distancing himself from the more academically-minded sort, such as the well-groomed Malcolm.
- Severus Snape from Harry Potter is often described with greasy, stringy hair, which only adds to his appearance as an Evil Teacher.
- Goosefeather in Warrior Cats almost never washes himself and has extremely bad breath, possibly due to his role as the Mad Oracle, and the fact that his prophecies are often misleading.
- Frequently alluded to by General Thiébault in his Mémoires; he seemed to measure how difficult and time-consuming his staff work was by the number of days he spent without shaving or changing clothes.
- A recurring theme in Scrubs is the difficulty of looking good while working at a hospital;
- "My Clean Break"'s B-Plot is about Elliot's habit of averting this (by getting up early), making the rest of the staff resent her.
- Another episode features Elliot herself trying to get around this trope while chatting up an attractive patient.
- Ted the lawyer always looks a mess thanks to his status as Dr. Kelso's whipping boy (and constantly dealing with lawsuits).
- An episode of Seinfeld has Jerry and Kramer swap apartments. Thanks to a "Kenny Roger's Roasters" sign which shines into Kramer's window, this happens to Jerry:
Jerry: [imitating Kramer's body language] Oh,...I'm stressed!
- In Battlestar Galactica (2003)'s first "real" episode ("33"), Adama and Tigh are both sporting very noticeable facial hair. As the characters have been attacked near constantly for a week, this is understandable.
- In Star Trek: Deep Space Nine this is used as shorthand to show that there's something physically wrong with a changeling. If Odo has gone too long without a regeneration cycle his usually immaculate uniform starts to darken and flake and his slicked-back hair gets crazy. Also seen with the female Founder in the last season, courtesy of Section 31's bioweapon.
- Community: In one of the documentary episodes, the Dean gets Annie to work as a script supervisor while he directs a commercial. He suffers from a severe case of Sanity Slippage, and after several days of putting up with his increasingly bizarre demands, Annie is completely out of it and ungroomed. She rationalizes the Dean's behaviour because she doesn't want to admit that she's wasted several weeks of her life helping him.
- The great detective Columbo, the walking epitome of shabby-efficient. Like Sam Vimes, his wife appears to make sure he's better groomed off the job.
- Lampshaded in "Negative Reaction" when he enters a soup kitchen and one of the volunteers mistakes him for a vagrant. When he explains he's a detective, she assumes he's working undercover in a disguise.
- In Angel, the biggest sign of Wesley's increasing competence is that he starts spending less and less time on his appearance and manners.
- The video for "Le Café" by Oldelaf features an office worker who slowly deteriorates thorough the day, thanks to the stress caused by work and too much coffee. The result is played for Black Comedy.
- Wilson, the basic character of Don't Starve, grows a beard over time in the game's permanent survival situation. It can even be used as a crafting ingredient.
- RWBY: Doctor Bartholomew Oobleck has an untidy look (mismatched shoes, untucked shirt, unfastened tie, Messy Hair) and only stops rushing around to take a swig of coffee. He's appropriately enthusiastic (and yet serious) about history.
- A downplayed example with Blake occurs during episodes 5 and 6 of the second volume. She develops dark undereye circles (which, combined with her skin and colour scheme, made her look like Cesare, to reflect how she refuses to sleep when trying to track down Torchwick.
- Dr. Stein of Blood Stain is initially always seen with Messy Hair likened to dry bramble and wearing lab coats stained by what is hopefully ketchup. Elliot imagines him as a Mad Scientist from first impressions, but Dr. Stein explains that his appearance is due to him being The Insomniac from working long hours on his job.
- Girl Genius:
- Vanamonde von Mekkahn is seen looking a disheveled with stubble after spending days preping for an inevitable follow up attack on Mechanicsburg.
- After the time skip Gil is shown with stubble, dark circles, red eyes and rumpled clothes due to spending the last two and a half years fighting of the Other and numerous rebels and insurrectionists all while he trying to figure out a way to undo the time stop on Mechanicsburg and save Agatha and Tarvek as well as everyone else in town.
- Stressed Eric plays this trope for laughs with the main character. As he gets more stressed, the vein on his temple throbs until it eventually bursts out and strangles him. Naturally, his environment tends to be rather cluttered, too.
- Twilight Sparkle of My Little Pony: Friendship is Magic has a tendency to turn into a disheveled mess whenever stressed or preoccupied. She usually ends up turning her library inside out in the process. Exaggerated in "Lesson Zero" (where forgetting to write a letter causes her to almost go completely insane).
- Wander over Yonder: The titular character suffers stress from being prevented from helping, or from his curiosity being denied but doing so actually clears it up. The stress takes the form of his eyes changing color, pupils changing size, his fur getting frizzy and brittle, and patches appearing on his hat.
- The 100th episode of The Simpsons introduces Principal Skinner with a dishevelled appearance from having a hectic day in his office.
- In Steven Universe, Peridot's hair becomes less of a perfect triangle the longer she's stranded on Earth knowing it's about to be destroyed.
- In season 3 episode "The Rickshank Rickdemption" of Rick and Morty, Mantis/Cronenberg universe from "Rick Potion No. 9" Jerry has a big, bushy beard.