The jet black Night Fury dragon that appeared alongside main protagonist Hiccup as the deuteragonist in the 2010 movie "How To Train Your Dragon". He is initially aggressive towards Hiccup but becomes friends with him after Hiccup helps Toothless become airborne again, after Toothless' left tail fin was ripped off when Hiccup shot him down.
Noun:

Person: Dude, Toothless is my favorite dragon EVER.
by SSG1 February 9, 2018
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A species of fire breathing dragons with black, sleek scales. This reptile is deemed to be dangerous and deadly, however when befreinded, the dragon will become a sort of guardian. The name "toothless" derives from the dragon's mouth which looks like it has the absense of teeth; but in times of danger, the dragon's vicious teeth are exposed.

The species was featured in the recent film, "How to Train your Dragon"
While playing tennis, the girl felt a crisp wind move her shot in-bounds and she knew Toothless, her guardian was in her presence.
by kridwid September 28, 2010
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When your ass let’s out a wet fart
*farts* “old toothless back there talking shit
by Steve cracked August 26, 2020
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somebody who's sleezy or unbelievably sneaky
that girl is toothless
by S Stizzle February 24, 2008
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Maude's got a proper toothless sealion going on down there, you can smell her biff on the chair when she was sitting in
by PYeti March 24, 2023
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