Could he sing a wrong note right? (5)
I believe the answer is:
tenor
'could he sing a' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'wrong note right?' is the wordplay.
'wrong' is an anagram indicator.
'right?' becomes 'r' (common abbreviation).
'note' is an anagram of 'teno'.
'teno'+'r'='TENOR'
Can you help me to learn more?
(Other definitions for tenor that I've seen before include "Singer; drift" , "direction" , "High voice - low bell" , "Highest male voice" , "General drift or meaning" .)