1.) hookup (v)
hook-up, hook up, hooked up, hooking up
To have any form of intamicy with a member of the prefered sex that you don't consider a significant other. Usually, when said by modern youth it means to make out, and when said by people between the ages of 20 and 35 it generally means to have sex, and if a very old person says it, it probbably means to simply spend time with somebody.
2.) hookup (v)
hooked up, hooking up, hook (pronoun) up
To give or sell something to somebody, usually in reference to drugs
3.) hookup (n)
hookups, hook-up(s), hook up(s)
A reference; a person capable of doing something; a connection
17 year old: dude i hooked up with jill yesterday, and she had horrible breath! i almost puked in her mouth
24 year old: i hooked up with patricia last night, but that bitch wanted me to put it in her ass so i left!
60 year old: back in the old day, me and my friends would always hookup and play some football down by the lake.
16 year old: Hook me up with some of that silver cush!
Napoleon dynomite: are you pedros cousins with all the sweet hookups?