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]