Completely reveal entitlement (8)
I believe the answer is:
outright
'completely' is the definition.
(thesaurus)
'reveal entitlement' is the wordplay.
'reveal' becomes 'out' (outing is a kind of revealing).
'entitlement' becomes 'right' (I've seen this before).
'out'+'right'='OUTRIGHT'
(Other definitions for outright that I've seen before include "Not qualified" , "straight away" , "Without restriction or reservation" , "Completely and entirely, not gradually" , "Altogether; openly" .)