Things you can't do with child, running around (2-3)
I believe the answer is:
no-one
'things' is the definition.
(I know that No One is a pseudonym)
'you can't do with child running around' is the wordplay.
I cannot quite see how this works, but
'you' could be 'one' (I've seen this before) and 'one' is found in the answer.
'around' could be 'o' (a round letter) and 'o' is found in the answer.
A single letter 'n' 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 no-one that I've seen before include "Not a soul" , "Not one person" , "Not a single person" , "Nobody" .)