sinful (adj.)youdaoicibaDictYouDict[sinful 词源字典]
Old English synnfull "full of sin, wicked, unholy, contrary to the laws of God;" see sin (n.) + -ful. Weakened sense of "contrary to propriety or decency" is from 1863. Related: Sinfully; sinfulness.[sinful etymology, sinful origin, 英语词源]