Not good. Bad.

The early Jazz musicians would say that a guy could really "Blow" if he had a good sound when playing the horn. If he couldn't play very well then they would say that he was "Sucking" on that horn. That's where the term "Suck" as being something bad came from.

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.

is not good. is, in fact, bad.

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.

when something is a bit downheartening or lame

What you life is by being on Urban Dictionary all the time and looking up words like 'sucks' when you obviously know what it means, your just looking for a cheap thrill.

to be really really crappy