Furtive way with money? Not wife! (8)
I believe the answer is:
stealthy
'furtive' is the definition.
(synonyms)
'way with money? not wife' is the wordplay.
'way' becomes 'st' (abbreviation for street).
'with money?' becomes 'wealthy' (wealthy people have money).
'not' is a deletion indicator.
'wife' becomes 'w' (abbreviation).
'wealthy' with 'w' removed is 'ealthy'.
'st'+'ealthy'='STEALTHY'
(Other definitions for stealthy that I've seen before include "'Furtive, surreptitious (8)'" , "Acting in furtive or covert manner" , "Underhand" , "Moving surreptitiously" , "Covert - clandestine" .)