Note that no real hacker calls themself a 'hacker'. That's just a media term.
hack -- a clever solution to a problem that has some beautiful aesthetics, or also defined as some messy solution that does work but isn't great.
e.g., a hack may be that you've reduced a 100 line program to 80 lines, using some little-known features of that programming language ('that's a neat hack'). or it may be some ugly setup you've made to get something done that works but isn't at all nice to setup or would be complicated to explain to someone else ('i hacked it together').
most people that call themselves hackers and see it from the popular media view are young teenagers that have found some ready-made (canned) program online somewhere that is meant to let you 'hack' into your friends' computers and play about opening their CD drive etc. not really very cool.