The Collaborative International Dictionary of English v.0.48:

Infant \In"fant\, n. [L. infans; pref. in- not + fari to speak:
   cf. F. enfant, whence OE. enfaunt. See Fame, and cf.
   Infante, Infanta.]
   1. A child in the first period of life, beginning at his
      birth; a young babe; sometimes, a child several years of
      age.
      [1913 Webster]

            And tender cries of infants pierce the ear. --C.
                                                  Pitt.
      [1913 Webster]

   2. (Law) A person who is not of full age, or who has not
      attained the age of legal capacity; a person under the age
      of twenty-one years; a minor.
      [1913 Webster]

   Note: An infant under seven years of age is not penally
         responsible; between seven and fourteen years of age,
         he may be convicted of a malicious offense if malice be
         proved. He becomes of age on the day preceding his
         twenty-first birthday, previous to which time an infant
         has no capacity to contract.
         [1913 Webster]

   3. Same as Infante. [Obs.] --Spenser.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Infant \In"fant\, a.
   1. Of or pertaining to infancy, or the first period of life;
      tender; not mature; as, infant strength.
      [1913 Webster]

   2. Intended for young children; as, an infant school.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Infant \In"fant\, v. t. [Cf. F. enfanter.]
   To bear or bring forth, as a child; hence, to produce, in
   general. [Obs.]
   [1913 Webster]

         This worthy motto, "No bishop, no king," is . . .
         infanted out of the same fears.          --Milton.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

193 Moby Thesaurus words for "infant":
   abecedarian, aboriginal, adolescent, angel, antenatal, apprentice,
   arrested, autochthonous, babe, babish, baby, baby bunting, babyish,
   bambino, bantling, bay, beginner, beginning, budding, callow,
   catechumen, child, child of nature, classmate, creative, deb,
   debutant, defective, deficient, doll-like, dollish, dove, dupe,
   elemental, elementary, embryonic, entrant, failing, fellow student,
   fetal, fledgling, formative, foundational, freshman, fundamental,
   gestatory, grade schooler, green, greenhorn, greeny, hick,
   high schooler, hopeful, hypoplastic, immature, in arms, in arrear,
   in arrears, in default, in diapers, in embryo, in its infancy,
   in nappies, in short supply, in swaddling clothes, in the bud,
   in the cradle, inadequate, inaugural, inceptive, inchoate,
   inchoative, incipient, incomplete, incubator baby, incunabular,
   infantile, infantine, ingenue, initial, initiative, initiatory,
   innocent, intermediate schooler, introductory, inventive, junior,
   juvenal, juvenile, kindergartner, kittenish, lacking, lamb,
   learner, little angel, little darling, lout, mere child,
   mewling infant, minor, missing, nascent, natal, needing, neonatal,
   neonate, neophyte, nestling, newborn, newborn babe, newcomer,
   noble savage, novice, novitiate, nursery school child, nursling,
   oaf, original, papoose, part, partial, parturient, patchy,
   postnatal, preemie, pregnant, premature baby, prenatal,
   prep schooler, preschool child, preschooler, primal, primary,
   primary schooler, prime, primeval, primitive, primogenial,
   probationer, procreative, pubescent, puling infant, raw recruit,
   recruit, rookie, rube, rudimental, rudimentary, sapling, scant,
   scanty, school child, school kid, school lad, schoolboy,
   schoolfellow, schoolgirl, schoolmate, scrappy, secondary schooler,
   short, shy, simple soul, sketchy, slip, sprig, stripling, suckling,
   teenager, teener, teenybopper, tenderfoot, toddler, trainee, tyro,
   underdeveloped, undeveloped, unfledged, unripe, unsophisticate, ur,
   wanting, weanling, yearling, yokel, young hopeful, young person,
   younger, youngest, youngling, youngster, youth, youthful