Professional.
1)Doing something and
getting paid.
2)Your profession. You
get paid to carry out your profession.
3)In gaming, if somebody is pro they are very good at the game, although they may or may not have won cash prize tournaments of the game.
4)The
pros of an argument/idea/product .etc.
1)Tom is a professional drummer, and he's been paid to play worldwide with various groups.
2)I'm a
post man. That's my profession, and i get paid to deliver post.
3)nubz0rcakes_356 is an
uber pro at DotA, he pwns.
4)The pros of this product are that it is very cheap and will save alot of energy.
The cons are that it isn't resistant to water.