Why can't people who use the word "cool"?
define it?
I notice that in all sections of YA one sees the word used but any attempt to find out what the user means by it is ignored. I wouldn't feel happy to use and reuse a word that I didn't actually know the meaning of.
Before anyone offers it - the answer that "if you need to ask you would not understand" is a symptom oif the problem not an answer to it!
Rolf, your comment resolved into the "if you need to ask............." bit that I did say was part of the problem and not an answer. The word 'cool' is actually getting used when someone recognises the need for an adjective but doesn't know many.