Sound fruit (5)
I believe the answer is:
plumb
'sound fruit' is the definition.
'plumb' can be an answer for 'sound' (thesaurus). I'm unsure of the 'fruit' bit.
'sound fruit' is the wordplay.
'sound' shows a homophone (sound like).
'fruit' becomes 'plum' (plum is a kind of fruit).
'plum' sounds like 'PLUMB'.
Can you help me to learn more?
(Other definitions for plumb that I've seen before include "Exactly - in a vertical line" , "Exactly - . . . . . in the middle" , "Going straight up and down" , "Test alignment" , "Lead weight; exactly" .)