A co-worker that lures you in to thinking that mediocrity is commonplace at the office. Just when you think you are both on the same page he or she will make look bad by putting together elite spreadsheets, cutting edge PowerPoints, and insightful talking points at meetings.
John: Where is Lindsay? She normally takes a 2 hour lunch with us?
Jim: Oh you didn't know? Turns out she is a closet overachiever.
Jim: Oh you didn't know? Turns out she is a closet overachiever.
by TR DUDE November 21, 2013

Hey bro, I don't go down like that. I go down like this. Come on man, don't you have a wife and kids? Yes, it's not like I'm gay, I'm just closet straight.
by Chef boy ar Gee December 31, 2014

Someone who seems really chill and relaxed but periodically suggests something very dark or unnerving.
by GlueBank February 28, 2017

a bro who plays your video games, eats your leftovers and lives in your coat closet under the stairs... for FREE!
by skyskier December 20, 2008

Hey Bob, Did you see Hilary Swank on the Oscar's Show last night in that low-cut see-through dress?? Man, she's got huge beautiful Mogambos!!! I can't believe that she had that 'closet rack' in the movie 'Boys Don't Cry'! I'm so happy to see that 'they' finally came out! Those titties are truly 'Million Dollar Babies'!!
by Florida Sunshine November 9, 2009

one who displays librarian-like tendencies despite their best efforts to hide them; in fact they usually make no efforts to hide them whatsoever.
by NOTMYNECK August 13, 2007

A male who appears to be friendly but turns out to be a massive asshole when you really get to know him
by fooddetector December 14, 2014
