The Collaborative International Dictionary of English v.0.48:

Rusty \Rust"y\, a. [AS. rustig.] [Compar. Rustier; superl.
   Rustiest.]
   1. Covered or affected with rust; as, a rusty knife or sword;
      rusty wheat.
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   2. Impaired by inaction, disuse, or neglect.
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            [Hector,] in this dull and long-continued truce,
            Is rusty grown.                       --Shak.
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   3. Discolored and rancid; reasty; as, rusty bacon.
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   4. Surly; morose; crusty; sullen. [Obs. or Prov. Eng.] "Rusty
      words." --Piers Plowman.
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   5. Rust-colored; dark. "Rusty blood." --Spenser.
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   6. Discolored; stained; not cleanly kept; filthy.
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            The rusty little schooners that bring firewood from
            the British provinces.                --Hawthorne.
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   7. (Bot.) Resembling, or covered with a substance resembling,
      rust; affected with rust; rubiginous.
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