The Collaborative International Dictionary of English v.0.48:

naive \na*ive"\, naive \na*["i]ve"\(n[aum]*[=e]v"), a. [F.
   na["i]f, fem. na["i]ve, fr. L. nativus innate, natural,
   native. See Native, and cf. Na["i]f.]
   1. Having native or unaffected simplicity; ingenuous;
      artless; frank; as, na["i]ve manners; a na["i]ve person;
      na["i]ve and unsophisticated remarks.
      [1913 Webster]

   2. Having a lack of knowledge, judgment, or experience;
      especially, lacking sophistication in judging the motives
      of others; credulous; as, a naive belief in the honesty of
      politicians.
      [PJC]

WordNet (r) 3.0 (2006):

naive
    adj 1: marked by or showing unaffected simplicity and lack of
           guile or worldly experience; "a teenager's naive
           ignorance of life"; "the naive assumption that things can
           only get better"; "this naive simple creature with wide
           friendly eyes so eager to believe appearances" [syn:
           naive, naif] [ant: sophisticated]
    2: of or created by one without formal training; simple or naive
       in style; "primitive art such as that by Grandma Moses is
       often colorful and striking" [syn: primitive, naive]
    3: inexperienced
    4: lacking information or instruction; "lamentably unenlightened
       as to the laws" [syn: uninstructed, unenlightened,
       naive]
    5: not initiated; deficient in relevant experience; "it seemed a
       bizarre ceremony to uninitiated western eyes"; "he took part
       in the experiment as a naive subject" [syn: uninitiate,
       uninitiated, naive]

Moby Thesaurus II by Grady Ward, 1.0:

116 Moby Thesaurus words for "naive":
   artless, awkward, befoolable, blankminded, bluff, blunt,
   born yesterday, budding, callow, candid, childlike, confiding,
   credulous, cullible, deceivable, deludable, dependent, depending,
   dewy, direct, dumb, dupable, easy, empty, empty-headed,
   exploitable, foolable, frank, fresh, gauche, green, groping,
   growing, guileless, gullible, hoaxable, hoodwinkable, humbugable,
   ignorant, immature, impubic, inane, inexperienced, ingenu,
   ingenuous, innocent, intact, juicy, know-nothing, minor, nescient,
   new-fledged, open, openhearted, original, outspoken, persuadable,
   plain, raw, reliant, relying, ripening, sappy, seduceable, simple,
   simplehearted, simpleminded, sincere, single-hearted,
   single-minded, soft, strange to, susceptible, tender, tentative,
   trustful, trusting, trusty, unacquainted, unadult, unaffected,
   unapprized, unartificial, uncomprehending, unconversant, underage,
   undeveloped, unenlightened, unfamiliar, unfledged, unformed,
   unguarded, unilluminated, uninformed, uninitiated, unintelligent,
   unknowing, unlicked, unmellowed, unposted, unreserved, unripe,
   unschooled, unseasoned, unsophisticated, unstudied, unsure,
   unsuspecting, unsuspicious, unversed, unwary, vacuous, vernal,
   victimizable, virginal, without suspicion



The Jargon File (version 4.4.7, 29 Dec 2003):

naive
 adj.

    1. Untutored in the perversities of some particular program or system; one
    who still tries to do things in an intuitive way, rather than the right way
    (in really good designs these coincide, but most designs aren't ?really
    good? in the appropriate sense). This trait is completely unrelated to
    general maturity or competence, or even competence at any other specific
    program. It is a sad commentary on the primitive state of computing that
    the natural opposite of this term is often claimed to be experienced user
    but is really more like cynical user.

    2. Said of an algorithm that doesn't take advantage of some superior but
    advanced technique, e.g., the bubble sort. It may imply naivete on the
    part of the programmer, although there are situations where a naive
    algorithm is preferred, because it is more important to keep the code
    comprehensible than to go for maximum performance. ?I know the linear
    search is naive, but in this case the list typically only has half a dozen
    items.? Compare brute force.


The Free On-line Dictionary of Computing (30 December 2018):

naive

   Untutored in the perversities of some particular program or
   system; one who still tries to do things in an intuitive way,
   rather than the right way (in really good designs these
   coincide, but most designs aren't "really good" in the
   appropriate sense).  This trait is completely unrelated to
   general maturity or competence or even competence at any other
   specific program.  It is a sad commentary on the primitive
   state of computing that the natural opposite of this term is
   often claimed to be "experienced user" but is really more like
   "cynical user".

   (1994-11-29)