The Collaborative International Dictionary of English v.0.48:

Gentle \Gen"tle\, a. [Compar. Gentler; superl. Gentlest.]
   [OE. gentil, F. gentil noble, pretty, graceful, fr. L.
   gentilis of the same clan or race, fr. gens, gentis, tribe,
   clan, race, orig. that which belongs together by birth, fr.
   the root of genere, gignere, to beget; hence gentle,
   properly, of birth or family, that is, of good or noble
   birth. See Gender, and cf. Genteel, Gentil, Gentile,
   Gentoo, Jaunty.]
   1. Well-born; of a good family or respectable birth, though
      not noble.
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            British society is divided into nobility, gentry,
            and yeomanry, and families are either noble, gentle,
            or simple.                            --Johnson's
                                                  Cyc.
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            The studies wherein our noble and gentle youth ought
            to bestow their time.                 --Milton.
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   2. Quiet and refined in manners; not rough, harsh, or stern;
      mild; meek; bland; amiable; tender; as, a gentle nature,
      temper, or disposition; a gentle manner; a gentle address;
      a gentle voice.
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   3. A compellative of respect, consideration, or conciliation;
      as, gentle reader. "Gentle sirs." "Gentle Jew." "Gentle
      servant." --Shak.
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   4. Not wild, turbulent, or refractory; quiet and docile;
      tame; peaceable; as, a gentle horse.
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   5. Soft; not violent or rough; not strong, loud, or
      disturbing; easy; soothing; pacific; as, a gentle touch; a
      gentle gallop . "Gentle music." --Sir J. Davies.
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            O sleep! it is a gentle thing.        --Coleridge.
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   The gentle craft, the art or trade of shoemaking.

   Syn: Mild; meek; placid; dovelike; quiet; peaceful; pacific;
        bland; soft; tame; tractable; docile.

   Usage: Gentle, Tame, Mild, Meek. Gentle describes the
          natural disposition; tame, that which is subdued by
          training; mild implies a temper which is, by nature,
          not easily provoked; meek, a spirit which has been
          schooled to mildness by discipline or suffering. The
          lamb is gentle; the domestic fowl is tame; John, the
          Apostle, was mild; Moses was meek.
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The Collaborative International Dictionary of English v.0.48:

Gentle \Gen"tle\, n.
   1. One well born; a gentleman. [Obs.]
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            Gentles, methinks you frown.          --Shak.
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   2. A trained falcon. See Falcon-gentil.
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   3. (Zool.) A dipterous larva used as fish bait.
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The Collaborative International Dictionary of English v.0.48:

Gentle \Gent"le\, v. t.
   1. To make genteel; to raise from the vulgar; to ennoble.
      [Obs.] --Shak.
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   2. To make smooth, cozy, or agreeable. [R. or Poet.]
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            To gentle life's descent,
            We shut our eyes, and think it is a plain. --Young.
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   3. To make kind and docile, as a horse. [Colloq.] Gentlefolk

WordNet (r) 3.0 (2006):

gentle
    adj 1: soft and mild; not harsh or stern or severe; "a gentle
           reprimand"; "a vein of gentle irony"; "poked gentle fun
           at him" [syn: gentle, soft]
    2: having or showing a kindly or tender nature; "the gentle
       touch of her hand"; "her gentle manner was comforting"; "a
       gentle sensitive nature"; "gentle blue eyes"
    3: quiet and soothing; "a gentle voice"; "a gentle nocturne"
    4: belonging to or characteristic of the nobility or
       aristocracy; "an aristocratic family"; "aristocratic
       Bostonians"; "aristocratic government"; "a blue family";
       "blue blood"; "the blue-blooded aristocracy"; "of gentle
       blood"; "patrician landholders of the American South";
       "aristocratic bearing"; "aristocratic features"; "patrician
       tastes" [syn: aristocratic, aristocratical, blue,
       blue-blooded, gentle, patrician]
    5: easily handled or managed; "a gentle old horse, docile and
       obedient" [syn: docile, gentle]
    6: having little impact; "an easy pat on the shoulder"; "gentle
       rain"; "a gentle breeze"; "a soft (or light) tapping at the
       window" [syn: easy, gentle, soft]
    7: marked by moderate steepness; "an easy climb"; "a gentle
       slope" [syn: easy, gentle]
    v 1: cause to be more favorably inclined; gain the good will of;
         "She managed to mollify the angry customer" [syn: pacify,
         lenify, conciliate, assuage, appease, mollify,
         placate, gentle, gruntle]
    2: give a title to someone; make someone a member of the
       nobility [syn: ennoble, gentle, entitle]
    3: stroke soothingly

Moby Thesaurus II by Grady Ward, 1.0:

310 Moby Thesaurus words for "gentle":
   accepting, acclimate, acclimatize, accommodate, accustom, adapt,
   adjust, affable, agreeable, ambling, amiable, appease,
   aristocratic, balmy, barely audible, bed, bed down, benign, bland,
   bleeding, bonhomous, break, break in, break to harness, bridle,
   broken, brush, bust, calm, calm down, case harden, cautious,
   charitable, chastened, chivalrous, circumspect, claudicant,
   clement, commiserative, compassionate, complaisant, compose,
   condition, condolent, confirm, controllable, cool, cordial, cradle,
   crawling, creeping, creeping like snail, cultivated, cultured,
   curry, currycomb, cushion, dainty, decrescendo, deliberate,
   delicate, dim, distant, docile, domesticate, domesticated,
   domesticize, dovelike, drench, ducal, dulcify, ease, easy,
   easy-natured, easygoing, establish, even out, exalted, faint,
   faint-voiced, faltering, familiarize, feeble, feed, fix, flagging,
   fluff, fodder, foot-dragging, forbearant, forbearing, forgiving,
   genial, genteel, gentlemanlike, gentlemanly, good-humored,
   good-natured, good-tempered, gracious, gradual, groom, habituate,
   halcyon, half-heard, halting, handle, harden, harness, high,
   highbred, hitch, hobbled, hobbling, housebreak, housebroken, human,
   humane, humble, hush, hushed, idle, indistinct, indolent,
   indulgent, inure, judicious, kind, kindly, kinglike, kingly, knead,
   knightly, ladylike, lamblike, languid, languorous, lax, laxate,
   lazy, leisurely, lenient, light, limber, limber up, limping,
   litter, loosen, low, lull, lumbering, manage, manageable, mash,
   massage, meek, mellow, mellowy, melting, merciful, mild,
   mild as milk, milden, milk, moderate, mollified, mollify, murmured,
   naturalize, noble, nonresistive, nonrigid, nonviolent,
   of gentle blood, of rank, orient, orientate, pacific, pacifistic,
   pacify, patient, patrician, peaceable, peaceful, pianissimo, piano,
   pitying, placid, pleasant, pleasing, plump, poking, poky, polished,
   pour balm into, princelike, princely, prudent, pulp, queenlike,
   queenly, quell, quiet, quite the lady, refined, relax, relaxed,
   reluctant, rest, restful, rock, rock to sleep, rub down, ruthful,
   saddle, sauntering, scarcely heard, season, serene, shake up,
   shuffling, slack, slothful, slow, slow as death, slow as molasses,
   slow as slow, slow-crawling, slow-foot, slow-going, slow-legged,
   slow-moving, slow-paced, slow-poky, slow-running, slow-sailing,
   slow-stepped, sluggish, smash, smooth, smooth down, smooth over,
   smoothen, snail-paced, snaillike, sober, soft, soft as putty,
   soft-sounding, soft-voiced, soften, soften up, softened,
   softhearted, soothe, soothing, squash, stabilize, staggering,
   steady, still, strolling, subaudible, subdue, subdued, supple,
   sweet, sweet-tempered, sympathetic, sympathizing, tame, tamed,
   temperate, tend, tender, tenderhearted, tenderize, tentative,
   thoughtful, titled, toddling, tolerant, tone down, tortoiselike,
   tottering, tractable, train, tranquil, tranquilize, trudging,
   tune down, turtlelike, unclear, understanding, undisturbed,
   unhurried, unruffled, untroubled, waddling, warmhearted, water,
   weak, weak-voiced, well-bred, well-brought-up, well-natured,
   whisper-soft, whispered, wont, yoke