WordNet (r) 3.0 (2006):

not guilty
    adj 1: declared not guilty of a specific offense or crime;
           legally blameless; "he stands acquitted on all charges";
           "the jury found him not guilty by reason of insanity"
           [syn: acquitted, not guilty]

Moby Thesaurus II by Grady Ward, 1.0:

24 Moby Thesaurus words for "not guilty":
   angelic, blameless, childlike, clear, dovelike, faultless,
   guiltless, in the clear, incorrupt, innocent, lamblike,
   offenseless, prelapsarian, pristine, reproachless, sans reproche,
   sinless, uncorrupted, undefiled, unfallen, unlapsed,
   untouched by evil, with clean hands, without reproach



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

NOT GUILTY, pleading. The general issue in several sorts of actions. It is
the general issue.
     2. In trespass, its form is as follows: "And the said C D, by E F, his
attorney, comes and defends the, force and injury, when, &c., and says, that
he is not guilty of the said trespasses above laid to his charge, or any
part thereof, in the manner and form as the said A B hath above complained.
And of this the said C D puts himself upon the country."
     3. Under this issue the defendant may give in evidence any matter which
directly controverts the truth of any allegation, which the plaintiff on
such general issue will be bound to prove; 1 B. & P. 213; and no person is
bound to justify who is not, prima facie, a trespasser. 2 B. & P. 359: 2
Saund. 284, d. For example, the plea of not guilty is proper in trespass to
persons, if the defendant have committed no assault, battery, or
imprisonment, &c.; and in trespass to personal property, if the plaintiff
had no property in the goods, or the defendant were not guilty of taking
them, &c.; and in trespass to real property, this plea not only puts in
issue the fact of trespass, &c, but also the title, which, whether freehold
or possessory in the defendant, or a person under whom he claims, may be
given in evidence under it, which matters show, prima facie, that the right
of possession, which is necessary in trespass, is not in the plaintiff, but
in the defendant or the person under whom he justifies. 8 T. R. 403; 7 T. R.
354; Willes, 222; Steph. PI. 178; 1 Chit. PI. 491, 492.
     4. In trespass on the case in general, the formula is as follows: "And
the said C D, by E F his attorney, comes and defends the wrong and injury
when, &c., and says, that he is not guilty of the premises above laid to his
charge, in manner and form as the said A B hath above complained. And of
this the said C D puts himself on the country."
     5. This, it will be observed, is a mere traverse, or denial, of the
facts alleged in the declaration; and therefore, on principle, should be
applied only to cases in which the defence rest's on such denial. But here a
relaxation has taken place, for under this plea, a defendant is permitted
not only to contest the truth of the declaration, but with some exceptions,
to prove any matter of defence, that tends to show that the plaintiff has no
cause of action, though such matters be in confession and avoidance of the
declaration; as, for example, a release given, or satisfaction made. Steph.
Pl. 182-3; 1 Chit. Pi. 486.
     6. In trover. It is not usual in this action to plead any other plea,
except the statute of limitations; and a release, and the bankruptcy of the
plaintiff, may be given in evidence under the general issue.  7 T. R. 391
     7. In debt on a judgment suggesting a devastavit, an executor may plead
not  guilty. 1 T. R. 462.
     8. In criminal cases, when the defendant  wishes to put himself on his
trial, he pleads  not guilty.