Correct girth, maybe (5)
I believe the answer is:
right
'correct' is the definition.
('right' can be a synonym of 'correct')
'girth maybe' is the wordplay.
'maybe' is an anagram indicator.
'girth' with letters rearranged gives 'RIGHT'.
(Other definitions for right that I've seen before include "Morally good; rectify" , "The hand to the east when facing north" , "ideal" , "Fit" , "It's what you deserve" .)