smut: [16] Smut is a member of a large but loosely-knit family of West Germanic words beginning with sm and ending in t or d that convey the general notion of ‘putting dirt on something’. Others include German schmutzen ‘get dirty’ and English smudge [15], and also English smite, which originally meant ‘smear’. Smut itself may have been borrowed from Low German smutt. => smite, smudge[smut etymology, smut origin, 英语词源]