The Collaborative International Dictionary of English v.0.48:

Transgress \Trans*gress"\, v. t. [imp. & p. p. Transgressed;
   p. pr. & vb. n. Transgressing.] [Cf. F. transgresser. See
   Transgression.]
   1. To pass over or beyond; to surpass. [R.]
      [1913 Webster]

            Surpassing common faith, transgressing nature's law.
                                                  --Dryden.
      [1913 Webster]

   2. Hence, to overpass, as any prescribed as the ?imit of
      duty; to break or violate, as a law, civil or moral.
      [1913 Webster]

            For man will hearken to his glozing lies,
            And easily transgress the sole command. --Milton.
      [1913 Webster]

   3. To offend against; to vex. [Obs.]
      [1913 Webster]

            Why give you peace to this imperate beast
            That hath so long transgressed you ?  --Beau. & Fl.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Transgress \Trans*gress"\, v. i.
   To offend against the law; to sin.
   [1913 Webster]

         Who transgressed in the thing accursed.  --I Chron. ii.
                                                  7.
   [1913 Webster]

WordNet (r) 3.0 (2006):

transgress
    v 1: act in disregard of laws, rules, contracts, or promises;
         "offend all laws of humanity"; "violate the basic laws or
         human civilization"; "break a law"; "break a promise" [syn:
         transgress, offend, infract, violate, go against,
         breach, break] [ant: keep, observe]
    2: spread over land, especially along a subsiding shoreline;
       "The sea transgresses along the West coast of the island"
    3: commit a sin; violate a law of God or a moral law [syn:
       sin, transgress, trespass]
    4: pass beyond (limits or boundaries) [syn: transgress,
       trespass, overstep]

Moby Thesaurus II by Grady Ward, 1.0:

61 Moby Thesaurus words for "transgress":
   advance upon, breach, breach the law, break, break bounds,
   break the law, care naught for, circumvent the law, commit a crime,
   commit sin, contravene, defy, disobey, disobey the law, disregard,
   disregard the law, do amiss, do violence to, do wrong, encroach,
   err, exceed, fall from grace, flout, go astray, go beyond,
   go counter to, go too far, go wrong, ignore, infract, infringe,
   intrude, invade, irrupt, know no bounds, lapse, make an inroad,
   misbehave, not conform, not heed, not keep, not listen, not mind,
   not observe, offend, overstep, overstep the bounds,
   refuse to cooperate, scoff at, set at defiance, set at naught,
   set naught by, sin, trample on, trample underfoot, trample upon,
   trespass, usurp, violate, violate the law