Separate identity given in disreputable bar (6)
I believe the answer is:
divide
'separate' is the definition.
(separate can mean to divide or split)
'identity given in disreputable bar' is the wordplay.
'identity' becomes 'id' (abbreviation).
'given in' indicates putting letters inside.
'disreputable bar' becomes 'dive' ().
'id' put into 'dive' is 'DIVIDE'.
(Other definitions for divide that I've seen before include "Bisect" , "Partition. separate" , "Saying : '. . . . . . and conquer'" , "Part" , "draw between 13A & 19" .)