1 definition by AkuKnives

An individual who frequently strives to have a complete set of something, regardless of whether or not the individual pieces have any importance or value.
Boy: I've almost caught every single Pokémon!
Girl: Aren't there like 700 something now? You can't possibly raise them all.
Boy: Yeah, but I HAVE to catch them all!
Girl: Ugh, you're such a Completionist!
by AkuKnives October 13, 2014
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