Mind is vacant accepting opposing points? (6)
I believe the answer is:
beware
'mind' is the definition.
(both can be used as a word of warning)
'vacant accepting opposing points?' is the wordplay.
'vacant' becomes 'bare'.
'accepting' is an insertion indicator.
'opposing points?' becomes 'ew' (east and west).
'bare' going around 'ew' is 'BEWARE'.
'is' acts as a link.
(Other definitions for beware that I've seen before include "Archaic word for look out, mind yourself" , "Wee bra (anag)" , "Take heed" , "Archaic injunction to be careful, look out" , "Cry of warning" .)