[adjective]He confessed that he had sinful thoughts.(informal) Buying that new car was a sinful waste of money (= it was morally wrong to spend so much money on it).(figurative informal) This cream cake is sinful (= tastes very good, but is bad for you)!
SINFUL
Meaning of SINFUL in English
Cambridge English vocab. Кембриджский английский словарь. 2012