Leave, terribly angry about being exposed (8)
I believe the answer is:
revealed
'being exposed' is the definition.
(I've seen this in another clue)
'leave terribly angry about' is the wordplay.
'terribly' indicates an anagram.
'angry' becomes 'red' (someone may go red when angry).
'about' is an insertion indicator.
'leave' is an anagram of 'veale'.
'veale' put into 'red' is 'REVEALED'.
(Other definitions for revealed that I've seen before include "Made known to others" , "Exposed" , "Made clear and visible" , "'Made known, disclosed (8)'" , "Discovered" .)