Egg supplier, though this man's good at tennis (3)
I believe the answer is:
hen
'egg supplier' is the definition.
(I've seen this in another clue)
'this man's good at tennis' is the wordplay.
'this man' becomes 'he' (he refers to a man).
'good at tennis' becomes 'n' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'he'+'n'='HEN'
'though' acts as a link.
Can you help me to learn more?
(Other definitions for hen that I've seen before include "Source of eggs" , "This party is for women only" , "Insufficient in amount" , "Adult female chicken" , "Clucking female" .)