Meat cost regularly on reflection is a swindle (4)
I believe the answer is:
scam
'is a swindle' is the definition.
(I've seen this before)
'meat cost regularly on reflection' is the wordplay.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
'on reflection' says the letters should be written backwards.
'meat'+'cost'='meatcost'
The alternate letters of 'meatcost' are 'macs'.
'macs' in reverse letter order is 'SCAM'.
(Other definitions for scam that I've seen before include "Rip off" , "Fraudulent business scheme" , "Screw" , "Swindle (Slang)" , "fiddle" .)