Silly but not exactly dotty (5)

I believe the answer is:

potty

I'm a little stuck... Click here to teach me more about this clue!

This could be a double definition.

'silly' is the first definition.
(thesaurus)

'not exactly dotty' is the second definition.
'potty' can be an answer for 'dotty' (thesaurus). I am not certain of the 'not exactly' bit.

'but' is the link.

Can you help me to learn more?

(Other definitions for potty that I've seen before include "Daft (informal)" , "sort of chamber?" , "Infant's loo" , "Bonkers" , "Crazy (colloq.)" .)

I've seen this clue in the Evening Standard.

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