Facebook Check

noun/verb: to inspect the Facebook profile of a potential boyfriend, girlfriend, random hookup to see if he/she is in a relationship before proceeding to make advances. This is done to avoid socially making an ass of oneself. Danger: Sometimes, Facebook Checking may open the door for a Facebook Stalker.This is also done to see if the desired person is loose or stuck up.

When you meet someone online, (tinder, plenty of fish, ok Cupid, etc.) and you want to make sure they're not a total psycho before you meet them. So you look them up on Facebook to see what they post, who they're friends with, what pictures you haven't seen, etc. Sometimes you are surprised by what you find...

When you are bored or you've been away from Internet access or just whenever you log in to Facebook over and over even though pretty much nothing changes, but you just do it to a) have something to do b) make sure no one's magically done something cool. Called such because it's like when you're hungry or (more likely) bored and so you keep checking the fridge in the hopes that something new and exciting will appear, even though you know it's just week-old leftovers.