Variant, a.
Etymology: [L. varians, p. pr. of variare to change: cf. F. variant. See Vary.]
1. Varying in from, character, or the like; variable; different; diverse.
2. Changeable; changing; fickle. [Obs.] He is variant, he abit [abides] nowhere. Chaucer.
1 other Webster entry under this spelling
Variant, n.
Something which differs in form from another thing, though really the same; as, a variant from a type in natural history; a variant of a story or a word.
Shades of meaning
Fernald has no entry of its own for variant; he lists it under heterogeneous.
He lists it without comment; the entries above explain its neighbors.