One who does no work may be riled (5)
I believe the answer is:
idler
'one who does no work' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'may be riled' is the wordplay.
'may' indicates an anagram (I've seen 'might' mean this (I've seen this in other clues)).
'riled' with letters rearranged gives 'IDLER'.
Can you help me to learn more?
(Other definitions for idler that I've seen before include "Lazy type" , "Wastrel; The ---, Dr Johnson essays" , "one averse to work" , "Slacker" , "Unpowered guide pulley" .)