Rust | Webster's Dictionary (1865)

Rŭst, n.

noun

n. [A-S. & Dan. rust, D. roest, Ger. & Sw. rost, Icel. ryd, Prov. Ger. rott, W. rhwd, probably from its color, and allied to rud, ruddy, red, as Lat. rubigo is from ruber, red.]

The reddish or brownish yellow coating on iron exposed to moist air; an oxide of iron which forms a rough coat on its surface; hence, sometimes, any metallic oxide.
That which resembles rust in appearance or effects; as, (a.) A composition of iron-filings and sal-ammoniac mixed with water, used to fill up joints in iron-work, &c. (b.) A dust-like parasitic fungus or mushroom which forms on the leaves and stalks of many kinds of grain. (c.) Any foul matter contracted; as, rust on corn or salted meat. (d.) Hence, corrosive or injurious accretion or influence. “Sacred truths cleared from all rust and dross of human mixtures.” K. Charles.

☞ Rust is sometimes used in the formation of compounds of very obvious meaning; as, rust-colored, rust-consumed, rust-eaten, and the like.

Rūst, v. i.

verbintransitive

v. i. [imp. & p. p. RUSTED; p. pr. & vb. n. RUSTING.] [A-S. rustian, Ger. rosten, W. rhydn.]

Sense 1. To contract rust; to be oxidized, and contract a roughness on the surface.

Our armors now may rust. Dryden.

Sense 2. To degenerate in idleness; to become dull by inaction.

Must I rust in Egypt, never more Appear in arms and be the chief of Greece? Dryden.

Sense 3. To gather dust or extraneous matter.

Rŭst, v. t.

verbtransitive

v. t. 1. To cause to contract rust; to corrode with rust. Keep up your bright swords, for the dew will rust them. Shak. 2. To impair by time and inactivity. Johnson.