- intruding or tending to intrude; constituting intrusion
- Geol. designating or of igneous rock formed from magma that hardened while still within the earth, moon, etc.
- Phonet. present or added in speech although not represented originally in spelling or accounted for otherwise etymologically (Ex.: the d added to OE spinel to form spindle)
Origin of intrusivefrom Classical Latin intrusus, past participle of intrudere (see intrude) + -ive