Partially retired middleman enjoys dental cover (6)
I believe the answer is:
enamel
'cover' is the definition.
(thesaurus)
'partially retired middleman enjoys dental' is the wordplay.
'retired' says the letters should be written in reverse.
'partially' says the answer is hidden in the clue.
'lemane' is hidden in the letters of 'middleman enjoys dental'.
'lemane' backwards is 'ENAMEL'.
(Other definitions for enamel that I've seen before include "Outer tooth material" , "Hard type of paint" , "Hard, glossy protective coating" , "Ale men (anag.)" , "Hard substance covering teeth" .)