1. cool (adjective): someone who is good-looking or attractive
She thinks the guy is really cool, but she doesn't know him like I do.
2. PG (noun): parental guidance
The movie is rated PG, so I think we should watch it before we take the kids to see it.
3. come on (phrasal verb): used to express that something said is unreasonable
Come on, Mom. You can't expect me clean up my room before I go out tonight, can you? .