Tarnish, v. t. [imp. & p. p. Tarnished; p. pr. & vb. n. Tarnishing.]
Etymology: [F. ternir, fr. OHG. tarnen to darken, to conceal, hide; akin to OS. dernian to hide, AS. dernan, dyrnan, OHG. tarni hidden, OS. derni, AS. derne, dyrne. Cf. Dern, a., and see -ish.]
To soil, or change the appearance of, especially by an alternation induced by the air, or by dust, or the like; to diminish, dull, or destroy the luster of; to sully; as, to tarnish a metal; to tarnish gilding; to tarnish the purity of color. "Tarnished lace." Fuller. Used also figuratively; as, to tarnish one's honor.
Syn. -- To sully; stain; dim.
2 other Webster entries under this spelling
Tarnish, v. i.
To lose luster; to become dull; as, gilding will tarnish in a foul air. Till thy fresh glories, which now shine so bright, Grow stale and tarnish with our daily sight. Dryden.
Tarnish, n.
1. The quality or state of being tarnished; stain; soil; blemish.
2. (Min.)
A thin film on the surface of a metal, usually due to a slight alteration of the original color; as, the steel tarnish in columbite.
Shades of meaning
Fernald has no entry of its own for tarnish; he lists it under blemish, defile, stain.
He lists it without comment; the entries above explain its neighbors.