"tameness, gentleness, mildness," late 14c., from L. mansuetudo "tameness," from mansuetus, pp. of mansuescere "to tame," lit. "to accustom to the hand," from manus "hand" (see
manual) + suescere "to accustom, habituate," from PIE *swdh-sko-, from base *s(w)e- (see
idiom).