Boy jumping up and down? (3)
I believe the answer is:
bob
'up and down?' is the definition.
'boy jumping' is the wordplay.
I cannot quite understand how this works, but
'boy' could be 'bo' and 'bo' is present in the answer.
A single letter 'b' remains which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for bob that I've seen before include "Quick curtsy" , "short hair" , "Briefly curtsy; hair style" , "Bow" , "Curtsy quickly" .)