OT character in trouble, vindicated (4)
I believe the answer is:
levi
'ot character' is the definition.
(I've seen this before)
'in trouble vindicated' is the wordplay.
'in' says the answer is hidden in the clue.
'LEVI' is hidden within 'trouble vindicated'.
(Other definitions for levi that I've seen before include "Matthew the apostle" , "Biblical priest" , "Jewish priestly tribe" , "Jacob's son (OT)" , "The Strauss who first patented blue jeans" .)