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]

WordNet (r) 3.0 (2006):

infant
    n 1: a very young child (birth to 1 year) who has not yet begun
         to walk or talk; "the baby began to cry again"; "she held
         the baby in her arms"; "it sounds simple, but when you have
         your own baby it is all so different" [syn: baby, babe,
         infant]

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



Bouvier's Law Dictionary, Revised 6th Ed (1856):

INFANT, persons. One under the age of twenty-one years. Co. Litt. 171.
     2. But he is reputed to be twenty-one years old, or of full age, the
first instant of the last day of the twenty-first year next before the
anniversary of his birth; because, according to the civil computation of
time, which differs from the natural computation, the last day having
commenced, it is considered as ended. Savig. Dr. Rom. Sec. 182. If, for
example, a person were born at any hour of the first day of January, 1810,
(even a few minutes before twelve o'clock of the night of that day,) he
would be of full age at the first instant of the thirty-first of December,
1831, although nearly forty-eight hours before he had actually attained the
full age of twenty-one years, according to years, days, hours and minutes,
because there is, in this case, no fraction of a day. 1 Sid. 162; S. C. 1
Keb. 589; 1 Salk. 44; Raym. 84; 1 Bl. Com. 463, 464, note 13, by Chitty; 1
Lilly's, Reg. 57; Com. Dig. Enfant, A; Savig. Dr. Rom. Sec.  383, 384.
     3. A curious case occurred in England of a young lady who was born
after the house clock had struck, while the parish clock was striking, and
before St. Paul's had begun to strike twelve on the night of the fourth and
fifth of January, 1805, and the question was whether she was born on the
fourth or fifth of January. Mr. Coventry gives it as his opinion that she
was born on the fourth, because the house clock does not regulate anything
but domestic affairs, that the parochial clock is much better evidence, and
that a metropolitan clock ought to be received with "implicit acquiescence."
Cov. on Conv. Ev. 182-3. It is conceived that this can only be prima facie,
because, if the fact were otherwise, and the parochial and metropolitan
clocks should both have been wrong, they would undoubtedly have had no
effect in ascertaining the age of the child.
     4. The sex makes no difference, a woman is therefore an infant until
she has attained her age of twenty-one years. Co. Litt. 171. Before arriving
at full infant may do many acts. A male at fourteen is of discretion, and
may consent to marry; and at that age he may disagree to and annul a
marriage he may before that time have contracted he may then choose a
guardian and, if his discretion be proved, may, at common law, make a will
of his personal estate; and may act as executor at the age of seventeen
years. A female at seven may be betrothed or given in marriage; at nine she
is entitled to dower; at twelve may consent or disagree to marriage; and, at
common law, at seventeen may act as executrix.
     5. Considerable changes of the common law have probably taken place in
many of the states. In Pennsylvania, to act as an executor, the party must
be of full age. In general, an infant is not bound by his contracts, unless
to supply him for necessaries. Selw. N. P. 137; Chit. Contr. 31; Bac. Ab.
Infancy, &c. I 3; 9 Vin. Ab. 391; 1 Com. Contr. 150,.151; 3 Rawle's R. 351;
8 T. R. 335; 1 Keb. 905, 913; S. C. 1 Sid. 258; 1 Lev. 168; 1 Sid. 129; 1
Southard's R. 87. Sed vide 6 Cranch, 226; 3 Pick. 492; 1 Nott & M'Cord, 197.
Or, unless he is empowered to enter into a contract, by some legislative
provision; as, with the consent of his parent or guardian to put himself
apprentice, or to enlist in the service of the United States. 4 Binn. 487; 5
Binn. 423.
     6. Contracts made with him, may be enforced or avoided by him on his
coming of age. See Parties to contracts; Voidable. But to this general rule
there is an exception; he cannot avoid contracts for necessaries, because
these are for his benefit. See Necessaries. The privilege of avoiding a
contract on account of infancy, is strictly personal to the infant, and no
one can take advantage of it but himself. 3 Green, 343; 2 Brev. 438. When
the contract has been performed, and it is such as he would be compellable
by law to perform, it will be good and bind him. Co. Litt. 172 a. And all
the acts of an infant, which do not touch his interest, but take effect from
an authority which he has been trusted to execute, are binding. 3 Burr.
1794; Fonb. Eq., b. 1, c. 2, Sec. 5, note c.
     7. The protection which the law gives an infant is to operate as a
shield to him, to protect him from improvident contracts, but not as a sword
to do injury to others. An infant is therefore responsible for his torts,
as, for slander, trespass, and the like; but he cannot be made responsible
in an action ex delicto, where the cause arose on a contract. 3 Rawle's R.
351; 6 Watts' R. 9; 25 Wend. 399; 3 Shep. 233; 9 N. H. Rep. 441; 10 Verm.
71; 5 Hill, 391. But see contra, 6 Cranch, 226; 15 Mass. 359; 4 M'Cord, 387.
     8. He is also punishable for a crime, if of sufficient discretion, or
doli capax. 1 Russ. on Cr. 2, 3. Vide, generally, Bouv. Inst. Index, h.t.;
Bing. on Infancy; 1 Hare & Wall. Sel. Dec. 103, 122; the various
Abridgments and Digests, tit. Enfant, Infancy; and articles Age; Birth;
Capax Doli; Dead born; Foetus; In ventre sa mere.