Hit with tenth foul in poor kids' game (4,3,7)
I believe the answer is:
hunt the thimble
'kids' game' is the definition.
I don't know anything about this answer so I cannot judge whether this works.
'hit with tenth foul in poor' is the wordplay.
'with' says to put letters next to each other.
'foul' indicates an anagram.
'in' is an insertion indicator.
'poor' becomes 'humble' (I can't explain this - if you can you should believe this answer much more).
'hit' after 'tenth' is 'tenthhit'.
'tenthhit' is an anagram of 'ntthethi'.
'ntthethi' inserted inside 'humble' is 'HUNT THE THIMBLE'.
Can you help me to learn more?
(Other definitions for hunt the thimble that I've seen before include "Party game involving search" , "Children's game in which a digital protector is sought" .)