Rogue president's behind swindle (5)
I believe the answer is:
scamp
'rogue' is the definition.
(thesaurus)
'president's behind swindle' is the wordplay.
'president' becomes 'p' (common abbreviation eg in VP).
'behind' means one lot of letters go next to another.
'swindle' becomes 'scam' (scam is a kind of swindle).
'p' put after 'scam' is 'SCAMP'.
(Other definitions for scamp that I've seen before include "A young rascal misbehaving in camps" , "Little Devil" , "Rogue - perform inadequately" , "Mischief-maker" , "Impish child" .)