[1] : The Collaborative International Dictionary of English v.0.48

immature \im`mature"\, a. l. immaturus; pref. im- not +
   maturus mature, ripe. see mature.
   1. not mature; unripe; not arrived at perfection of full
      development; crude; unfinished; as, immature fruit;
      immature character; immature plans. "an ill-measured and
      immature counsel." --bacon.
      1913 webster

   2. premature; untimely; too early; as, an immature death.
      r. --jer. taylor.
      1913 webster
see also:
mature 

[2] : WordNet (r) 2.0

immature
     adj 1: characteristic of a lack of maturity; "immature behavior"
            ant: mature
     2: lacking in development; "immature plans"; "an unformed
        character" syn: unformed
     3: used of living things especially persons in an early
        period of life or development or growth; "young people"
        syn: young ant: old
     4: not fully developed or mature; not ripe; "unripe fruit";
        "fried green tomatoes"; "green wood" syn: green, unripe,
         unripened ant: ripe
     5: not yet mature ant: mature
     6: of birds not yet having developed feathers; "a small
        unfledged sparrow on the window sill" syn: unfledged
        ant: fledged
see also:
mature unformed young old green unripe 
unripened ripe unfledged fledged 

[3] : Moby Thesaurus II by Grady Ward, 1.0

152 moby thesaurus words for "immature":
   a novice at, a stranger to, adolescent, adulterated, amateur,
   amateurish, arrested, at half cock, babish, babyish, blemished,
   budding, callow, childish, childlike, dabbling, damaged, defective,
   deficient, dewy, dilettante, dilettantish, embryonic, erroneous,
   ever-new, evergreen, failing, fallible, faulty, firsthand,
   fledgling, found wanting, fresh, green, green as grass, growing,
   half-assed, half-baked, half-cocked, half-grown, hypoplastic,
   ignorant, ill-digested, impaired, imperfect, imprecise, impubic,
   impure, in arrear, in arrears, in default, in short supply,
   inaccurate, inadequate, incomplete, inexact, inexperienced, infant,
   infantile, infantine, ingenuous, innocent, intact, jejune, juicy,
   juvenile, lacking, maiden, maidenly, makeshift, mediocre, minor,
   missing, mixed, naive, needing, neoteric, nestling, new, new to,
   new-fledged, not perfect, off, original, part, partial, patchy,
   precocious, premature, pristine, puerile, raw, ripening,
   rudimentary, sappy, scant, scanty, sciolistic, scrappy,
   sempervirent, shallow, short, shy, sketchy, smattering, sophomoric,
   superficial, tender, unaccustomed to, unacquainted with, unadult,
   unbeaten, unconversant, unconversant with, underage,
   underdeveloped, underripe, undeveloped, uneven, unexperienced,
   unfamiliar with, unfinished, unfledged, unformed, ungrown,
   unhandled, uninitiated in, unlicked, unmatured, unmellowed,
   unperfected, unpracticed, unpracticed in, unripe, unseasoned,
   unskilled in, unsophisticated, unsound, unthorough, untouched,
   untried, untrodden, unused, unused to, unversed, unversed in,
   vernal, virgin, virginal, wanting, young, youthful

Immature >> I Words
Immature, definition of term: Immature
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