Not allowed appropriate rank (8)
I believe the answer is:
outright
'rank' is the definition.
(thesaurus)
'not allowed appropriate' is the wordplay.
'not allowed' becomes 'out' (I've seen this before).
'appropriate' becomes 'right' (similar in meaning).
'out'+'right'='OUTRIGHT'
(Other definitions for outright that I've seen before include "Completely and entirely, not gradually" , "Absolute - utter" , "Immediately; openly" , "Without restriction or reservation" , "Complete; immediately" .)