1) Hitting on, flirting, or generally just messing around with somebody whose taken.
Even jokingly.
2) Someone who commits the act of Cex. Someone who acts like a perv when others are making out, hugging, etc.
3) Used like sexy or shmexy, to
mean something cool.
"OMG did you just see that? that hot
chick was totally just cexing me!"
"dude: Aww
man I was just hittin on that hot
chick !
guy: Isnt she with her bf?
dude: yah... so?
guy: dude you are such a cex"
"that is so cex"