Pronunciation: (in-trOO'siv),[key] —adj. 1. tending or apt to intrude; coming without invitation or welcome: intrusive memories of a lost love. 2. characterized by or involving intrusion.
3. intruding; thrusting in.
4. Geol. a. (of a rock) having been forced between preexisting rocks or rock layers while in a molten or plastic condition.
b. noting or pertaining to plutonic rocks.
5. Phonet.excrescent (def. 2).