He's ready for a rhyme (5)
I believe the answer is:
eddie
'a rhyme' is the definition.
Both the definition and answer are singular nouns.
Perhaps you can see an association between them that I can't see?
'he's ready for' is the wordplay.
'he' becomes 'Edd'.
'ready for' becomes 'ie' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'edd'+'ie'='EDDIE'
Can you help me to learn more?
(Other definitions for eddie that I've seen before include "-- the Eagle, ski jumper" , "-- Izzard, comedian" , "Man" , "- Izzard, stand-up comic" , "Boy" .)