The Collaborative International Dictionary of English v.0.48:

Hardy \Har"dy\ (h[aum]r"d[y^]), a. [Compar. Hardier
   (-d[i^]*[~e]r); superl. Hardiest.] [F. hardi, p. p. fr. OF.
   hardir to make bold; of German origin, cf. OHG. hertan to
   harden, G. h[aum]rten. See Hard, a.]
   1. Bold; brave; stout; daring; resolute; intrepid.
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            Hap helpeth hardy man alway.          --Chaucer.
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   2. Confident; full of assurance; in a bad sense, morally
      hardened; shameless.
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   3. Strong; firm; compact.
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            [A] blast may shake in pieces his hardy fabric.
                                                  --South.
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   4. Inured to fatigue or hardships; strong; capable of
      endurance; as, a hardy veteran; a hardy mariner.
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   5. Able to withstand the cold of winter.
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   Note: Plants which are hardy in Virginia may perish in New
         England. Half-hardy plants are those which are able to
         withstand mild winters or moderate frosts.
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