The Collaborative International Dictionary of English v.0.48:

Candid \Can*did\ (k[a^]n"d[i^]d), a. [F. candide (cf. It.
   candido), L. candidus white, fr. cand[=e]re to be of a
   glowing white; akin to accend[e^]re, incend[e^]re, to set on
   fire, Skr. chand to shine. Cf. Candle, Incense.]
   1. White. [Obs.]
      [1913 Webster]

            The box receives all black; but poured from thence,
            The stones came candid forth, the hue of innocence.
                                                  --Dryden.
      [1913 Webster]

   2. Free from undue bias; disposed to think and judge
      according to truth and justice, or without partiality or
      prejudice; fair; just; impartial; as, a candid opinion.
      "Candid and dispassionate men." --W. Irving.
      [1913 Webster]

   3. Open; frank; ingenuous; outspoken.

   Syn: Fair; open; ingenuous; impartial; just; frank; artless;
        unbiased; equitable.

   Usage: Candid, Fair, Open, Frank, Ingenuous. A man
          is fair when he puts things on a just or equitable
          footing; he is candid when be looks impartially on
          both sides of a subject, doing justice especially to
          the motives and conduct of an opponent; he is open and
          frank when he declares his sentiments without reserve;
          he is ingenuous when he does this from a noble regard
          for truth. Fair dealing; candid investigation; an open
          temper; a frank disposition; an ingenuous answer or
          declaration.
          [1913 Webster]

WordNet (r) 3.0 (2006):

candid
    adj 1: characterized by directness in manner or speech; without
           subtlety or evasion; "blunt talking and straight
           shooting"; "a blunt New England farmer"; "I gave them my
           candid opinion"; "forthright criticism"; "a forthright
           approach to the problem"; "tell me what you think--and
           you may just as well be frank"; "it is possible to be
           outspoken without being rude"; "plainspoken and to the
           point"; "a point-blank accusation" [syn: blunt,
           candid, forthright, frank, free-spoken,
           outspoken, plainspoken, point-blank, straight-
           from-the-shoulder]
    2: informal or natural; especially caught off guard or
       unprepared; "a candid photograph"; "a candid interview"
    3: openly straightforward and direct without reserve or
       secretiveness; "his candid eyes"; "an open and trusting
       nature"; "a heart-to-heart talk" [syn: candid, open,
       heart-to-heart]

Moby Thesaurus II by Grady Ward, 1.0:

227 Moby Thesaurus words for "candid":
   Olympian, Spartan, aboveboard, accessible, all jaw, approachable,
   artless, ascetic, austere, authentic, bald, bare, bluff, blunt,
   bona fide, born yesterday, broad, brusque, card-carrying, chatty,
   childlike, common, commonplace, communicative, confiding,
   conversable, conversational, demonstrative, detached, dinkum,
   direct, disinterested, dispassionate, downright, dry, dull,
   effusive, equal, equitable, expansive, explicit, extroverted, fair,
   flip, fluent, following the letter, forthright, frank,
   frankhearted, free, free hand, free-acting, free-going,
   free-moving, free-speaking, free-spoken, free-tongued, freehanded,
   gabby, garrulous, gassy, genuine, glib, good, gossipy, gregarious,
   guileless, gushy, heart-to-heart, homely, homespun, honest,
   honest-to-God, impartial, impersonal, impromptu, inartificial,
   informal, ingenu, ingenuous, innocent, just, lawful, lean,
   legitimate, lifelike, literal, lofty, long-winded, loquacious,
   matter-of-fact, multiloquent, multiloquious, naive, native,
   natural, naturalistic, neat, neutral, newsy, objective, open,
   openhearted, original, outgoing, outspoken, overtalkative, plain,
   plain-speaking, plain-spoken, prolix, prosaic, prosing, prosy,
   pure, real, realistic, rightful, round, rustic, scrupulous,
   self-revealing, self-revelatory, selfless, severe, simon-pure,
   simple, simple-speaking, simplehearted, simpleminded, sincere,
   single-hearted, single-minded, smooth, sober, sociable, spare,
   stark, sterling, straight, straight-out, straightforward,
   sure-enough, talkative, talky, transparent, true to life,
   true to nature, true to reality, trustful, trusting, truthful,
   unadorned, unadulterated, unaffected, unartificial, unassumed,
   unassuming, unbiased, unbigoted, uncalculated, uncalculating,
   unchecked, uncolored, unconcealed, unconcocted, unconstrained,
   uncontrived, uncopied, uncounterfeited, undeceitful, undeceiving,
   undisguised, undisguising, undissembled, undissembling,
   undistorted, unequivocal, unexaggerated, unfabricated, unfanciful,
   unfeigned, unfeigning, unfictitious, unflattering, unguarded,
   unhampered, unimaginative, unimagined, unimitated, uninfluenced,
   uninvented, unpoetical, unprejudiced, unpremeditated, unpretended,
   unpretending, unpretentious, unqualified, unrepressed, unreserved,
   unrestrained, unrestricted, unreticent, unromantic, unsecretive,
   unselfish, unshrinking, unsilent, unsimulated, unsophisticated,
   unspecious, unsuppressed, unsuspicious, unswayed, unsynthetic,
   unvarnished, unwary, upright, verbal, verbatim, verbose, veridical,
   verisimilar, voluble, windy, word-for-word