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' shows that the letters should be reversed in order.
'partially' says the answer is hidden in the clue.
'lemane' can be found hidden inside '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" .)