Tailors struggling with the belly of Neil Diamond (9)
I believe the answer is:
solitaire
'diamond' is the definition.
(solitaire is a type of diamond)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for solitaire that I've seen before include "Patience game" , "Gem set by itself" , "Diamond; game for one" , "American singer" , "game > bird" .)