Reveal union ends with redhead after man (7)
I believe the answer is:
uncover
'reveal' is the definition.
('uncover' can be a synonym of 'reveal')
'union ends with redhead after man' is the wordplay.
'ends' suggests removing the centre.
'with' is a charade indicator (letters next to each other).
'redhead' becomes 'r' (the head/first letter of 'red').
'after' means one lot of letters go next to another.
'man' becomes 'cove' (I've seen this in other clues**).
'union' with its middle removed is 'un'.
'r' after 'cove' is 'cover'.
'un' put next to 'cover' is 'UNCOVER'.
(Other definitions for uncover that I've seen before include "bare" , "Take the lid off" , "show?" , "Expose, reveal" , "Make visible" .)