Toyed with or succumbed to the temptation to swindle (7)
I believe the answer is:
fiddled
'toyed' is the definition.
('fiddle' can be a synonym of 'toy')
'or succumbed to the temptation to swindle' is the wordplay.
I cannot quite understand how this works, but
'swindle' could be 'fiddle' (I've seen this before) and 'fiddle' is located in the answer.
A single letter 'd' remains which might be clued in a way I don't understand.
This explanation may well be incorrect...
'with' is the link.
Can you help me to learn more?
(Other definitions for fiddled that I've seen before include "Was corrupt" , "cheated" , "wasted time" , "What Nero did while Rome burned" .)