Source : Webster's Revised Unabridged Dictionary (1913)

Obtrusion \Ob*tru"sion\, n. [L. obtrusio. See {Obtrude}.]
   1. The act of obtruding; a thrusting upon others by force or
      unsolicited; as, the obtrusion of crude opinions on the
      world.

   2. That which is obtruded. --Milton.