amaranthine adj.

1610s, from French amarante, from Latin amarantus/amaranthus, from Greek amarantos, name of a mythical unfading flower, literally "unfading, undecaying," from a- "not" (see a- (3)) + stem of marainein "die away, waste away, decay, wither; quench, extinguish," from PIE root *mer- "to rub away, harm" (also "to die" and forming words referring to death and to beings subject to death).

In classical use, a poet's word for an imaginary flower that never fades. It was applied in botany to a genus of ornamental plants 1550s. The ending has been influenced by plant names from unrelated Greek -anthos "flower."

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.