Clothes pianist packs for the theatre (8)
I believe the answer is:
thespian
'the theatre' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'clothes pianist packs' is the wordplay.
'packs' says the answer is hidden in the clue (I've seen 'packing' mean this).
'THESPIAN' is hidden within 'clothes pianist'.
'for' is the link.
Can you help me to learn more?
(Other definitions for thespian that I've seen before include "cast member" , "Stage-player" , "stage performer" , "He paints (anag)" , "Tragic actor" .)