Time to argue for mutiny? (7)
I believe the answer is:
treason
'mutiny?' is the definition.
(I've seen this before)
'time to argue' is the wordplay.
'time' becomes 't' (abbreviation).
'to argue' becomes 'reason' (synonyms).
't'+'reason'='TREASON'
'for' is the link.
(Other definitions for treason that I've seen before include "Mutiny" , "Deliberate act of betrayal" , "One's art? (anag)" , "subversion" , "Lese-majesty" .)