The Collaborative International Dictionary of English v.0.48:

Rugged \Rug"ged\, a. [See Rug, n.]
   1. Full of asperities on the surface; broken into sharp or
      irregular points, or otherwise uneven; not smooth; rough;
      as, a rugged mountain; a rugged road.
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            The rugged bark of some broad elm.    --Milton.
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   2. Not neat or regular; uneven.
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            His well-proportioned beard made rough and rugged.
                                                  --Shak.
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   3. Rough with bristles or hair; shaggy. "The rugged Russian
      bear." --Shak.
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   4. Harsh; hard; crabbed; austere; -- said of temper,
      character, and the like, or of persons.
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            Neither melt nor endear him, but leave him as hard,
            rugged, and unconcerned as ever.      --South.
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   5. Stormy; turbulent; tempestuous; rude. --Milton.
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   6. Rough to the ear; harsh; grating; -- said of sound, style,
      and the like.
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            Through the harsh cadence of a rugged line.
                                                  --Dryden.
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   7. Sour; surly; frowning; wrinkled; -- said of looks, etc.
      "Sleek o'er your rugged looks." --Shak.
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   8. Violent; rude; boisterrous; -- said of conduct, manners,
      etc.
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   9. Vigorous; robust; hardy; -- said of health, physique, etc.
      [Colloq. U.S.]
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   Syn: Rough; uneven; wrinkled; cragged; coarse; rude; harsh;
        hard; crabbed; severe; austere; surly; sour; frowning;
        violent; boisterous; tumultuous; turbulent; stormy;
        tempestuous; inclement.
        [1913 Webster] -- Rug"ged*ly, adv. -- Rug"ged*ness,
        n.
        [1913 Webster]

WordNet (r) 3.0 (2006):

rugged
    adj 1: sturdy and strong in constitution or construction;
           enduring; "with a house full of boys you have to have
           rugged furniture" [ant: delicate]
    2: having long narrow shallow depressions (as grooves or
       wrinkles) in the surface; "furrowed fields"; "his furrowed
       face lit by a warming smile" [syn: furrowed, rugged]
       [ant: unfurrowed]
    3: topographically very uneven; "broken terrain"; "rugged
       ground" [syn: broken, rugged]
    4: very difficult; severely testing stamina or resolution; "a
       rugged competitive examination"; "the rugged conditions of
       frontier life"; "the competition was tough"; "it's a tough
       life"; "it was a tough job" [syn: rugged, tough]

Moby Thesaurus II by Grady Ward, 1.0:

204 Moby Thesaurus words for "rugged":
   Herculean, Spartan, Spartanic, abstruse, adamantine, arduous,
   asperous, astringent, austere, authoritarian, beefy, bitter, bold,
   bouncing, brawny, broken, brutal, bulky, bumpy, burdensome, burly,
   churlish, clownish, cockled, cockly, complex, corrugate,
   corrugated, cragged, craggy, creased, crimped, crimpy, crinkled,
   crinkly, critical, crude, crumpled, delicate, demanding, dense,
   difficile, difficult, doughty, dour, dry, durable, enduring,
   exacting, exigent, firm, flush, forceful, forcible, forcy,
   formidable, full-blooded, full-strength, furrowed, grating,
   gravelly, grim, gutsy, gutty, hairy, hale, hale and hearty, hard,
   hard as nails, hard-earned, hard-fought, hardy, harsh, hearty,
   heavy, hefty, hoarse, husky, ill-bred, inclement, independent,
   individualistic, intemperate, intricate, iron-hard, ironbound,
   irregular, jagged, jaggy, jarring, jawbreaking, knitted, knotted,
   knotty, laborious, lasting, loutish, lubberly, lumpish, lusty,
   massive, mean, meticulous, mighty, muscular, nervy, no picnic,
   not easy, obstinate, onerous, operose, pitted, potent, powerful,
   puckered, puckery, puissant, pursed, pursy, ragged, rasping,
   raucous, red-blooded, ridged, rigorous, rimpled, rippled, robust,
   robustious, robustuous, rockbound, rocky, rough, rough-and-ready,
   rucked, rude, rugose, rugous, rumpled, saw-toothed, sawtooth,
   scabrous, scragged, scraggly, scraggy, self-confident,
   self-reliant, self-sufficient, serrate, serrated, set with thorns,
   severe, snagged, snaggled, snaggy, solid, sound, spiny, stable,
   stalwart, steady, steely, steep, stern, stony, stout, strapping,
   strenuous, strict, stridulous, stringent, strong, strong as brandy,
   strong as strong, strong-willed, sturdy, thorny, ticklish,
   toilsome, tough, tricky, uncivilized, uncouth, uncultured, uneven,
   ungentle, ungraceful, unlevel, unpolished, unrefined, unsmooth,
   unsparing, unyielding, uphill, vigorous, vital, well-built,
   well-constructed, well-founded, well-grounded, well-made, wicked,
   wrinkled, wrinkly