Basic Trope: A Ninja who doesn't act like a ninja, meaning that they show little regard for matters like stealth.
Straight: Kodachi, a kunoichi, wears a bright blue getup and likes to divebomb her opponents while screaming "Death from Above!"
Exaggerated: Kodachi is a Large HamAttention Whore who wears a neon blue and black Stripperific outfit with more fishnet than fabric and turns everything she does into a big production. She also claims to be a master assassin.
Downplayed: Kodachi doesn't do much sneaking around, but she is difficult to see when she moves quickly.
It's estabilished in canon that all the enemies Kodachi fights are The Creatures Of The Darkness who can be literally blinded by the bright colours. Other characters don't adapt Kodachi's tactics because as a result of some curse they can't wear bright colours.
Her atypical behavior takes her opponents by surprise and messes with their strategies. Loud screams make them lose concentration. It also helps if because of her strange manners they don't take her seriously at first.
Her outfit has a pattern and material that function as a Weirdness Censor, effectively making her invisible even when leading a marching band worth of ninja.
Due to being ostracized, she deliberately wants to attract attention.
The bright colors are common, so even if they make it harder to fit in to the shadows, she blends into the crowd. She is also stealthy up to the point where she makes the kill, so by being loud she can see their look of surprise/horror. She is also commonly taking requests that have her kill a target that it would take a master to kill and not be noticed, so her cover is blown the second she goes into a kill, making her yelling pointless regardless, as she will be seen.
Inverted: Kodachi disguises herself as a normal but boisterous person to infiltrate an organization. No one suspects the buffoon, of ill intent, after all.
While every building and person in the setting wears bright neon and likes to pretend to be ninja (which would make a straight application of this trope justified), Kodachi wears the typical all black ninja garb, effectively standing out by not standing out.
Alternate: The bright outfits are the ninja equivalent of ceremonial uniforms. They only wear them when they want to be highly visible for political reasons.
Alternatively: Kodachi is just there as a decoy. While you're paying attention to her, you don't even notice her partner Sasuke peering around the corner, ready to put a poison dart in your back.
Except it turns out everyone thinks this is so lame, they ignore her and no one notices when she kills a target.
Alternate: But all of their missions are political, so they never wear their "work clothes".
Alternatively: You don't even notice her partner Sasuke... until he jumps out in an equally attention-grabbing outfit and shouts "POISON DART ATTACK!!!"
Kodachi keeps a floating dirigible with the words "Shhh! Ninja at work below!" in bright neon and aiming a spotlight over her current location at all times.
Kodachi's outfit glows in the dark, and is reflective to boot.
Zig Zagged: Kodachi draws unwanted attention because of her getup, except it can change to mimic background and grants her invisibility, the showyness is part of an act. But the act has let victims escape, except they wanted them to to make her seem weak.
Averted: Kodachi dresses and acts normally, blending into the background — as a good assassin should.
Enforced: "We need to make this show distinctive, and the ninja can't be too effective, so lets make them brightly colored!"
Lampshaded: "Who would hire assassins you could see in pitch black?"
Invoked: The hidden ninja school has a decoy academy with brightly colored ninja to make their own existence seem less likely.
Defied: Despite everyone else on the Five-Man Band wearing brightly colored get ups, Kodachi insists on wearing her infiltration gear.
Discussed: "I wonder why the Elder makes us wear these horrible uniforms?" *whap* "Silence your insolent tongue! The Elder is color blind, and yet he managed to kill more men than you've ever met."
Conversed: "Thank goodness the Spleen Ninja the Radioactive Octogenarian Lemures fight are so brightly colored, otherwise we'd never see them!"
Deconstructed: Kodachi's showboating and acting out quickly gets her killed, as she's an obvious threat and easily disposed of.
Kodachi can afford to be an Attention Whore because it turns out she's Just That Good. She's insanely skilled, and fully, infuriatingly aware of it — hence she's repeatedly sent on missions both due to her skills and because she's so loud and annoying her superiors hate having her around.
Or she's so good that she's gotten bored and is deliberately making things more challenging for herself.
Because she is so obvious, no one believes that she could be a ninja and people treat her as a wacko. In other words, she is hiding in plain sight.
Her highly visible style (and constant successes) cultivate her reputation to the point where all she has to do is show up and announce her target, and the target will commit seppuku on the spot, because he knows that he's doomed.
Plotted A Good Waste: While Kodachi and other members of her guild all appear to be Highly Visible Ninjas-In-Name-Only, it's eventually revealed that their leaders deliberately weed out the weakest clan members by picking them out, separating them from the better members, and teaching them to be flashy and highly visible as part of a "Special Secret Ninja Art" — which, unbeknownest to them, is the Art of Distraction. They're supposed to be Red Shirts, an acceptable loss so that their real agents go undetected and can fulfill their missions. Learning this causes Kodachi to have a Heroic BSOD and prompts her to defect from her guild and join the protagonists.
Played For Laughs: Kodachi isn't a very good ninja. Not that she realizes that.
Played For Drama: Kodachi's insistence on wearing this getup and being obvious causes her to suffer various defeats out of pride, eventually breaking her.