The Collaborative International Dictionary of English v.0.48:

Antique \An*tique"\, a. [F., fr. L. antiquus old, ancient,
   equiv. to anticus, from ante before. Cf. Antic.]
   [1913 Webster]
   1. Old; ancient; of genuine antiquity; as, an antique statue.
      In this sense it usually refers to the flourishing ages of
      Greece and Rome.
      [1913 Webster]

            For the antique world excess and pride did hate.
                                                  --Spenser.
      [1913 Webster]

   2. Old, as respects the present age, or a modern period of
      time; of old fashion; antiquated; as, an antique robe.
      "Antique words." --Spenser.
      [1913 Webster]

   3. Made in imitation of antiquity; as, the antique style of
      Thomson's "Castle of Indolence."
      [1913 Webster]

   4. Odd; fantastic. [In this sense, written antic.]
      [1913 Webster]

   Syn: Ancient; antiquated; obsolete; antic; old-fashioned;
        old. See Ancient.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Antique \An*tique"\, n. [F. See Antique, a. ]
   In general, anything very old; but in a more limited sense, a
   relic or object of ancient art; collectively, the antique,
   the remains of ancient art, as busts, statues, paintings, and
   vases.
   [1913 Webster]

         Misshapen monuments and maimed antiques. --Byron.
   [1913 Webster]

WordNet (r) 3.0 (2006):

antique
    adj 1: made in or typical of earlier times and valued for its
           age; "the beautiful antique French furniture"
    2: out of fashion; "a suit of rather antique appearance";
       "demode (or outmoded) attire"; "outmoded ideas" [syn:
       antique, demode, ex, old-fashioned, old-hat(p),
       outmoded, passe, passee]
    3: belonging to or lasting from times long ago; "age-old
       customs"; "the antique fear that days would dwindle away to
       complete darkness" [syn: age-old, antique]
    n 1: an elderly man [syn: old-timer, oldtimer, gaffer,
         old geezer, antique]
    2: any piece of furniture or decorative object or the like
       produced in a former period and valuable because of its
       beauty or rarity
    v 1: shop for antiques; "We went antiquing on Saturday"
    2: give an antique appearance to; "antique furniture" [syn:
       antique, antiquate]

Moby Thesaurus II by Grady Ward, 1.0:

194 Moby Thesaurus words for "antique":
   Gothic, Methuselah, Victorian, abandoned, abiding, abjured,
   age-long, age-old, aged, ageless, ago, ancestral, ancient,
   ancient manuscript, antediluvian, antiquated, antiquity, archaic,
   archaism, artifact, auld, back number, bibelot, blown over, by,
   bygone, bypast, cave painting, chronic, classical, collectable,
   conservative, constant, continuing, curio, dad, dated, dateless,
   dead, dead and buried, deceased, defunct, departed, deserted,
   discontinued, disused, diuturnal, dodo, done with, durable,
   elapsed, elder, elderly, enduring, eolith, evergreen, expired,
   extinct, finished, fogy, forgotten, fossil, fossilized, fud,
   fuddy-duddy, gone, gone glimmering, gone-by, granny, grown old,
   hardy, has-been, heirloom, hoary, immemorial, immutable,
   intransient, inveterate, irrecoverable, lapsed, lasting, legendary,
   long-lasting, long-lived, long-standing, long-term, longeval,
   longevous, longhair, macrobiotic, matriarch, medieval, mezzolith,
   microlith, mid-Victorian, mossback, neolith, no more,
   not worth saving, objet d'art, obsolescent, obsolete,
   of long duration, of long standing, of old, of other times,
   of yore, old, old as Methuselah, old as history, old as time,
   old believer, old crock, old dodo, old fogy, old liner, old man,
   old poop, old woman, old-fashioned, old-time, old-timer, old-timey,
   old-world, olden, oldfangled, on the shelf, out, out of date,
   out of use, out-of-date, outdated, outmoded, outworn, over,
   paleolith, passe, passed, passed away, past, past use, patriarch,
   pensioned off, perdurable, perduring, perennial, permanent,
   perpetual, persistent, persisting, petrification, petrified,
   petrified forest, petrified wood, petroglyph, plateaulith, pop,
   pops, rarity, reactionary, regular old fogy, relic, relinquished,
   reliquiae, remaining, remains, renounced, resigned, retired, ruin,
   ruins, run out, sempervirent, square, stable, starets, staying,
   steadfast, superannuate, superannuated, superseded, survival,
   timeless, timeworn, tough, traditional, traditionalist, unfading,
   vanished, venerable, vestige, vital, worn-out, wound up