Con-man - on the roof perhaps! (7)
I believe the answer is:
fiddler
'roof perhaps' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'con-man on' is the wordplay.
I cannot really understand how this works, but
'man' could be 'r' (abbreviation for rook, a chess piece or 'man') and 'r' is located in the answer.
The remaining letters 'fiddle' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'the' acts as a link.
Can you help me to learn more?
(Other definitions for fiddler that I've seen before include "Popular musical '. . . . . . . on the Roof'" , "Violinist - swindler - type of crab" , "Great musical ''....... on the roof''" , "Violinist (informal)" , "Violinist - cheat" .)