Fraud by heartless punks or rogues (6)
I believe the answer is:
scamps
'rogues' is the definition.
(I've seen this in another clue)
'fraud by heartless punks' is the wordplay.
'fraud' becomes 'scam' (scam is a kind of fraud).
'by' says to put letters next to each other.
'heartless' suggests removing the centre.
'punks' with its centre taken out is 'ps'.
'scam'+'ps'='SCAMPS'
'or' acts as a link.
(Other definitions for scamps that I've seen before include "Lively children" , "Little rascals, mischievous children" , "'Rascals, imps (6)'" , "Naughty little rascals" , "Mischevious young children" .)