He plays the piano on the pier, perhaps (5)
I believe the answer is:
'he plays' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'piano on the pier perhaps' is the wordplay.
'piano' becomes 'p' (musical abbreviation).
'on' means one lot of letters goes inside another.
'perhaps' indicates an anagram.
'pier' anagrammed gives 'iper'.
'p' placed inside 'iper' is 'PIPER'.
'the' acts as a link.
Can you help me to learn more?
(Other definitions for piper that I've seen before include "Wind instrumentalist" , "Military musician" , "who puffs out his cheeks?" , "Musical blower" , "See 21" .)