Can also mean a made-up slang word that no one understands.
Person 2: How was it sick? I find nothing sick with what I just did...
Person 1: No... "sick" can also mean "cool." Don't be so technical, and learn some slanguage, man!
Person 1: That was spawecoolerificness!
Person 2: Shut up with your made-up slanguage, idiot!