Aggro
Definition: aggressive behavior
Comes from the same prefix that gives us “aggression” and “aggravation.” Historically, the prefix meant “to approach” or “to attack.”
(See PS below. This might be a British idiom.)
Why I Looked It Up
On the TV show Manifest, a character said:
I didn’t want to interrupt because he was being so aggro.
It was pretty clear what it meant from context, but I had never heard the word before.
Postscript
Added on
This was a word in the NY Times crossword. The clue was:
Belligerent, in British slang