Tightfisted guy ultimately associated with scam (6)
I believe the answer is:
stingy
'tightfisted' is the definition.
(similar in meaning)
'guy ultimately associated with scam' is the wordplay.
'ultimately' says to take the final letters.
'associated with' is a charade indicator (letters next to each other).
'scam' becomes 'sting' (sting can mean a scam or deceptive scheme).
The last letter of 'guy' is 'y'.
'y' after 'sting' is 'STINGY'.
(Other definitions for stingy that I've seen before include "Tight-fisted, like 25 and 22 Across" , "Tight with money" , "Parsimonious like nettle?" , "Zola cocotte; Darlings' dog (Barrie)" , "reluctant to spend money" .)