What the nudist who's not at all busy has? (7,2)

'all busy has?' is the definition.
I know nothing about this answer so I can't tell whether this works.

'what the nudist who's not at' is the wordplay.
I cannot quite see how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is found in the answer.
'not' could be 'no' (negative) and 'no' is located in the answer.
'at' could be 'on' (location) and 'on' is present in the answer.
The remaining letters 'hing' is a valid word 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?