cool [kuːl], cool·er, the cool·est

[1] Having a slightly low temperature
[2] Of a person, knowing what to do and how to behave; considered popular by others
[3] In fashion, part of or fitting the in crowd; originally hipster slang

chilly, distant, phlegmatic, standoffish, unemotional, à la mode, fashionable, in fashion, modish, stylish, happening, hip, in, trendy, acceptable, all right, OK, easy, fine, not bothered, not fussed

• Unlike you, I am cool.
• That's a cool pencil case Lynn has there!
• I listen to cool music exclusively.