This is a supertrope/index with a number of tropes contained within. I had difficulty finding certain tropes on the page, and others I felt were related enough to make a supertrope for all of them. Not every character fights like the Knight in Shining Armor. Dirty fighting is a staple of many genres. It's regular appearance marks a work as more serious, 'gritty', and realistic (placing it appropriately on idealism/cynicism scale). There are lots of ways to work more 'resourceful' combatants into scenes and stories, but the key to good dirty fighting is twofold: a willingness on the part of the fighters to use whatever is available to them in combat, and a willingness to use psychological tricks in order to gain the upper hand. Anything goes in a real fight, after all. Subtropes follow
A Hand(ful) For An EyeThrowing sand in your opponent's eyes to temporarily blind them; favored by villainous characters. Seen It a Million Times; Do We Have This?
Hit Em While They're TalkingExactly What It Says on the Tin. We have to include this one simply because of the beauty of the opening quotes available to it.
Hari: And you don't block a groin-kick with your hands, you take it on the thigh. Every time you drop your hands, you're gonna get a whack. You understand?
Kris: Yes, I'm starting to -
Hari: *socks Kris in the solar plexus* Lesson two. Best time to hit someone is when he's off guard. Best time to catch someone off guard is when he's talking. When you talk, you're thinking about what to say next, not-
Kris: *belts Hari across the face*
Hari: ...Y'know, there's just the faintest chance I could start to like you.
-Blade of Tyshalle, by Matthew Woodring Stover
Oh ho ho ho! You sly dog! You caught me monologuing!
-Syndro from The IncrediblesNote: This is a major thing in Blade of Tyshalle. Caine in fact uses this trick in the climax to kill the reascendant Ma'elKoth. I Surrender, Suckers or split into its own trope?
The Dirty FighterA character who not only fights dirty on a reguar basis but is defined by his willingness to do anything in a fight to win. These guys are defined both by extensive knowledge of dirty fighting - they know that kneeing a girl in the crotch works - and by a willingness to use dirty fighting whenever beneficial - they have no compunctions against kneeing a girl there in a real fight. Needs a Better Title.