Old clothing for young goyim, regularly seen on the cricket field (8)
I believe the answer is:
Here is my best explanation:
'old clothing for young' is the definition.
I can't tell whether this definition defines the answer.
'goyim regularly seen on the cricket field' is the wordplay.
'regularly seen' indicates alternate letters.
'on' says to put letters next to each other.
'the cricket field' becomes 'slips' (I am not sure about this - if you are sure you should believe this answer much more).
The alternating letters of 'goyim' are 'gym'.
Can you help me to learn more?