Completionist 

Someone who, when playing a video game, has to collect all of a certain item, or complete something in the game 100%.

Only a completionist would collect all of the flags in Assassin's Creed.

Completionist by Cobbbler May 1, 2010

Completionist 

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!

Completionist by AkuKnives October 13, 2014

Completionist 

A person who feels compelled to attain every possible acheivement in whatever video game they play.

I got bored with this game ages ago but I'm a bit of a completionist, so I'm playing it on a harder difficulty level

Completionist by AIDSLOL October 21, 2010

Completionist 

A person who feels It is a necessity to obtain or achieve everything despite its INSIGNIFICANT value. They feel the need to turn everything into a collection from Disney figurines to sexual encounters with peers.

Peer: I'll give you a twenty bag to suck my dicc out here in the hundred acre woods
Robbie: *Muffled gagging noises*
Pooh: Oh bother!

Piglet: He can't help it, he's a completionist.

Completionist by OJSizzle February 24, 2017

Completionist 

A person who feels It is a necessity to obtain or achieve everything despite its significant value. They feel the need to turn everything into a collection from sexual encounters with children to snuff films

Luke: Aidan why have you stolen all Zacs chromosomes he can't function without them
Aidan: I can't help it I'm a completionist

Completionist by Melman Mankiewicz September 4, 2016

completionism

An overwhleming urge to find every collectible of a set or complet a game to 100%. Often associated with being a completionist.

My completionism led me to find every flag in Assasin's Creed

completionism by Catdrewz July 3, 2016

Complexionism 

Discrimination within a race against different shades of skin color.

A guy choosing to date light skinned African American women versus dark skinned African American women solely based on their skin is complexionism.

Complexionism by WillowB February 15, 2019