In Britain, ace means awesome. You'll hear it a lot when British people found something cool.
As a noun, "He is an ace at Math." As a verb, "I am going to ace that exam."
In American slang, an ace boon coon is a close friend.
Rad Tops Ace Rockin'
This isn't an idiom because it's just one word that's confusing. The word "ace" in this sense is slang. It means to score highly or make a top grade.
ACE High was created in 1956.
In poker, an ace is considered high.
palchumbuddypartnerHomie, Ace-Boon-Coon, , Right Hand
Ace Boom Town. Also recieve the Gloves
Bob Orton goes by Ace, and 'Cowboy' Bob Orton.
In cribbage, the ace is considered low, not high.
In Texas Hold'em, an ace is considered high.