Avoids name in supplement, playboys play a childish game (5,3,6)
I believe the answer is:
ducks and drakes
'game' is the definition.
(ducks and drakes is a kind of game)
'avoids name in supplement playboys play a childish' is the wordplay.
I cannot quite understand how this works, but
'avoids' could be 'ducks' (ducking is a kind of avoiding) and 'ducks' is found within the answer.
'name' could be 'n' (common abbreviation e.g. on forms) and 'n' is present in the answer.
'supplement' could be 'add' (I've seen this before) and 'add' is present in the leftover letters.
'a' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for ducks and drakes that I've seen before include "birds of both sexes" , "Mates" , "game, superficially bouncy" , "22 game" .)