musteline adj.

"animal of the family of mammals that includes the weasels, badgers, skunks, and otters," 1910, from Modern Latin Mustelidae, taken as a genus name by Linnaeus (1758), from Latin mustela "weasel," which is possibly a diminutive form from mus "mouse" (see mouse (n.)), a theory accepted by de Vaan, who writes, "The use of the dim. for the weasel can be due to its small size compared with other similar animals (marten, polecat) or because it was domesticated and used as a pet animal." Tucker tentatively suggests *mus-ters-la "mouse harrier," and Klein notes that the weasel was identified in antiquity as "the catcher of mice."

also -in, adjectival word-forming element, Middle English, from Old French -in/-ine, or directly from Latin suffix -inus/-ina/-inum "of, like," forming adjectives and derived nouns, as in divinus, feminus, caninus; from PIE adjectival suffix *-no- (see -en (2)).

The Latin suffix is cognate with Greek -inos/-ine/-inon, and in some modern scientific words the element is from Greek. Added to names, it meant "of or pertaining to, of the nature of" (Florentinus), and so it also was commonly used in forming Roman proper names, originally appellatives (Augustinus, Constantinus, Justinus, etc.) and its descendants in Romanic languages continued active in name-forming. The Latin fem. form, -ina, was used in forming abstracts (doctrina, medicina). Relics of the attempt to continue a distinction between Latin -ina and -inus account for the English hesitation in spelling between -in and -ine.