Foster 

To sign off randomly on people after they IM you.
To be bad at IM
(verb)

Dude this girl fostered me on IM today it so wasnt chilll man i didnt even mean to say hi to her....

Foster by Luke Foster Frodo October 27, 2010

foster 

A incredibly hot, damn fine piece of ass.

"man that leya is a total foster!"

"did you see that foster, Id love to hit that."

foster by L.E April 16, 2007

foster 

In regard to video games, to shoot an opposing player in either the crotch or ass. Also referred to as "Buttering" as in the episode of South Park where Butters shoots everyone in the crotch.

Guy 1: "Dude, you totally just shot him in the dick!"

Guy 2: "FOSTERED!"

foster by Arkem3 June 28, 2011

foster 

a word for someone who has more then one STD.

I know i have a foster on my cock after hooking up with that slam pig the other night.

foster by Barry Gorman October 12, 2006

foster 

to step on, usu. in a fight

That guy just fostered the other guy in the nuts.

foster by Excello April 13, 2008

foster 

no parents / orphan

foster: people with no parents

parents dont want the kids

kids live with their grandparents

foster by donthavetoknowme1 June 15, 2011

Foster 

Super athletic (mostly at football) and gets all of the laddies but only sticks to one and gets attached too easily.

Wow, that boy can really run the ball... yeah he must be a Foster.

Foster by Dan Hibbet December 5, 2016