If you suck, it generally means you have no skill and/or talent.
Oddly enoguh, even though suck is the opposite of blow, blow is an insult also.
1)A term meaning bad or not good
2)To put ones mouth over another object and pull air back. Often done in sexual ways.
1)Abby: I can't go to homecoming!
Rebecca: Wow. That sucks.
2)Camille sucks Mark's cock every night.
to be really really crappy
That team last night really sucked. They just plain sucked. I've seen teams suck before, but they were the suckiest buncha sucks that ever sucked.
A term refering to the vacuming by a female, to a males reproductive organs
Lora likes to suck my twig and berries
Not necessarily lacking in talent but expressing a general distaste for something or someone obnoxious, dull, detestable, abhorrent, etc.
The Steelers suck more than my new Hoover.
Not to confuse 'suck' with 'blow' as in: The Steelers blew like a third world prostitute.
to think that club penguin osts suck
Ryan: Club Penguin osts suck
some other dude: you suck