Maybe John cleaned for Frank (6)
I believe the answer is:
candid
'frank' is the definition.
(synonyms)
'maybe john cleaned' is the wordplay.
I cannot quite see how this works, but
'john' could be 'can' (both can informally mean toilet) and 'can' is present in the answer.
The remaining letters 'did' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
'for' acts as a link.
Can you help me to learn more?
(Other definitions for candid that I've seen before include "Truthful and straightforward" , "Frank - and CID (anag)" , "'Forthright, open (6)'" , "Free and frank" , "Frank and outspoken" .)