Dire omen disconcerted boss (8)
I believe the answer is:
domineer
'boss' is the definition.
(I've seen this before)
'dire omen disconcerted' is the wordplay.
'disconcerted' indicates an anagram.
'dire'+'omen'='direomen'
'direomen' is an anagram of 'DOMINEER'.
(Other definitions for domineer that I've seen before include "Behave imperiously" , "Dine more and be overbearing" , "behave arrogantly" , "Deem iron to be changed to overbear" , "Ore mined badly could tend to overbear" .)