Be like men prejudiced against women going topless (5)
I believe the answer is:
exist
'be' is the definition.
(I know that be can be written as exist)
'like men prejudiced against women going topless' is the wordplay.
'like men prejudiced against women' becomes 'sexist' (like sexist men).
'going topless' means to remove the first letter.
'sexist' with its initial letter taken off is 'EXIST'.
(Other definitions for exist that I've seen before include "Subsist" , "Have objective reality" , "Get a life!" , "quick!" , "Have being or continue living" .)