Hair transplant claim involving setters? (7)
I believe the answer is:
musical
'hair' is the definition.
(Hair is a musical)
'transplant claim involving setters?' is the wordplay.
'transplant' indicates anagramming the letters.
'involving' indicates putting letters inside.
'setters?' becomes 'us' (the crossword setter and their colleagues).
'claim' is an anagram of 'mical'.
'mical' placed around 'us' is 'MUSICAL'.
(Other definitions for musical that I've seen before include "Drama where songs are more important than plot" , "Cats maybe" , "Song and dance show" , "Annie or Mame, say" , "Stage entertainment" .)