Look out when worker admits conflict (6)
I believe the answer is:
beware
'look out' is the definition.
(bewaring is a kind of looking out)
'worker admits conflict' is the wordplay.
'worker' becomes 'bee' (I've seen this before).
'admits' indicates putting letters inside.
'conflict' becomes 'war' (war is a kind of conflict).
'bee' enclosing 'war' is 'BEWARE'.
'when' acts as a link.
(Other definitions for beware that I've seen before include "Be alert for dangers" , "cave" , "Wee bra (anag)" , "Archaic warning to watch out, danger ahead" , "Take heed" .)