The Collaborative International Dictionary of English v.0.48:

Obtrude \Ob*trude"\, v. t. [imp. & p. p. Obtruded, p. pr. &
   vb. n. Obtruding.] [L. obtrudere, obtrusum; ob (see Ob-)
   + trudere to thrust. See Threat.]
   1. To thrust impertinently; to present to a person without
      warrant or solicitation; as, to obtrude one's self upon a
      company; to obtrude one's opinion on another.
      [1913 Webster +PJC]

            The objects of our senses obtrude their particular
            ideas upon our minds, whether we will or no. --Lock.
      [1913 Webster]

   2. To offer with unreasonable importunity; to urge unduly or
      against the will. --Milton.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Obtrude \Ob*trude"\, v. i.
   To thrust one's self upon a company or upon attention; to
   intrude.
   [1913 Webster]

   Syn: To Obtrude, Intrude.

   Usage: To intrude is to thrust one's self into a place,
          society, etc., without right, or uninvited; to obtrude
          is to force one's self, remarks, opinions, etc., into
          society or upon persons with whom one has no such
          intimacy as to justify such boldness.
          [1913 Webster]

WordNet (r) 3.0 (2006):

obtrude
    v 1: push to thrust outward [syn: push out, obtrude, thrust
         out]
    2: thrust oneself in as if by force; "The colors don't intrude
       on the viewer" [syn: intrude, obtrude]

Moby Thesaurus II by Grady Ward, 1.0:

86 Moby Thesaurus words for "obtrude":
   barge in, boot out, bounce, break in, break in upon, burst in,
   butt in, cast, cast out, charge in, chuck out, come between, crash,
   crash in, crash the gates, creep in, crowd in, cut in,
   defenestrate, detrude, discard, discharge, edge in, eject,
   elbow in, encroach, entrench, exclude, expel, extrude, foist in,
   force upon, give the hook, heave out, horn in, impinge, impose,
   impose on, impose upon, infiltrate, infringe, insinuate, interfere,
   interlope, interpose, intervene, intrude, invade, irrupt, jettison,
   junk, kick downstairs, kick out, obtrude on, oust, press in,
   press upon, presume, push in, push upon, put on, put out, put upon,
   reject, remove, rush in, slink in, slip in, smash in, sneak in,
   squeeze in, steal in, storm in, throng in, throw away, throw out,
   throw overboard, thrust in, thrust out, thrust upon, toss out,
   trench, trespass, turn out, work in, worm in