Conflict in social worker's mind (6)
I believe the answer is:
beware
'mind' is the definition.
(both can be used as a word of warning)
'conflict in social worker's' is the wordplay.
'conflict' becomes 'war' (war is a kind of conflict).
'in' indicates putting letters inside.
'social worker' becomes 'bee' (bees work socially).
'war' inserted into 'bee' is 'BEWARE'.
(Other definitions for beware that I've seen before include "Archaic warning to be careful, danger ahead" , "See 18" , "Archaic warning to watch out, danger ahead" , "Word of warning" , "Stay alert to danger" .)