2
In Math, the complement is, simply put, that which is outside of the defined region. However, this is often used as an insult in geek circles.

Geek 1:Your momma's so fat, that she's the complement of your house.

Geek 2: Yeah, well at least my penis isn't always the complement of a vagina.

Geek 1: *shoots self, thus becoming the complement of existing*
by Evariste Galois April 20, 2009
Get the mug
Get a complement mug for your dog Abdul.
4
something you give to someone you like
something you add to food to improve its taste
She accepted the complement with good grace
by Philip Nash November 26, 2006
Get the mug
Get a complement mug for your barber Sarah.