slothful (adj.)youdaoicibaDictYouDict[slothful 词源字典]
c. 1400, from sloth + -ful. Related: Slothfully; slothfulness. For the latter, Middle English also had sloth-head (c. 1300), with Middle English -hede, cognate with -hood.[slothful etymology, slothful origin, 英语词源]