in·tru·sive / inˈtroōsiv/ • adj. 1. making an unwelcome manifestation with disruptive or adverse effect: that was an intrusive question tourist attractions that are environmentally intrusive. ∎  (of a person) disturbing another by one's uninvited or unwelcome presence: giving people information about their health without being too intrusive.2. Phonet. (of a sound) pronounced between words or syllables to facilitate pronunciation, such as an r in saw a movie , which occurs in the speech of some eastern New Englanders and metropolitan New Yorkers.3. Geol. of, relating to, or formed by intrusion.DERIVATIVES: in·tru·sive·ly adv.in·tru·sive·ness n.

intrusive Applied to a body of rock, usually igneous, that is emplaced within preexisting rocks. Intrusions are classified according to their size, their shape, and their geometrical relationship to the enclosing rocks.