Rude ace fined for insubordination (8)
I believe the answer is:
defiance
'for insubordination' is the definition.
(I've seen this before)
'rude ace fined' is the wordplay.
'rude' indicates an anagram.
'ace'+'fined'='acefined'
'acefined' anagrammed gives 'DEFIANCE'.
(Other definitions for defiance that I've seen before include "confrontation" , "Refusal to comply" , "Refusal to obey" , "Resistance to authority" , "open disobedience" .)