chill
"an adjective used to describe someone who you think is very cool, someone you'd like to spend time with. is generally used with a preceeding adverb, such as very, pretty, definitely, etc.
She is definitely chill; I'd like to be with her."
Look here for some other slang uses:
Urban Dictionary: chill
PS: Don't expect other people to understand these terms if you use them. But that dictionary can help you with some slang meanings.