Fix hat when leaving a fair (5)
I believe the answer is:
right
'fair' is the definition.
(thesaurus)
'fix hat when leaving a' is the wordplay.
'fix' becomes 'rig' (rig can mean to fix or manipulate).
'when leaving' suggests deleting specific letters.
'hat' with 'a' taken away is 'ht'.
'rig'+'ht'='RIGHT'
(Other definitions for right that I've seen before include "Not left" , "Correct; proper" , "Equitable" , "Fitting; entitlement" , "Morally defensible" .)