Rascal dismissing pressure to swindle (4)
I believe the answer is:
scam
'to swindle' is the definition.
(scam is a kind of swindle)
'rascal dismissing pressure' is the wordplay.
'rascal' becomes 'scamp' (synonyms).
'dismissing' indicates named letters should be taken away.
'pressure' becomes 'p' (abbreviation).
'scamp' with 'p' taken away is 'SCAM'.
(Other definitions for scam that I've seen before include "Swindle (Slang)" , "Rip off" , "A slangy swindle or fraud" , "Fraudulent scheme, swindle" , "Rip-off" .)