'Intrusive' definitions:

Definition of 'intrusive'

(from WordNet)
adjective
Tending to intrude (especially upon privacy); "she felt her presence there was intrusive" [ant: not intrusive, unintrusive]
adjective
Of rock material; forced while molten into cracks between layers of other rock [ant: extrusive]
adjective
Thrusting inward; "an intrusive arm of the sea" [ant: protrusive]

Definition of 'Intrusive'

From: GCIDE
  • Intrusive \In*tru"sive\, a. Apt to intrude; characterized by intrusion; entering without right or welcome. [1913 Webster]
  • Intrusive rocks (Geol.), rocks which have been forced, while in a plastic or melted state, into the cavities or between the cracks or layers of other rocks. The term is sometimes used as equivalent to plutonic rocks. It is then contrasted with effusive or volcanic rocks. -- {In*tru"sive*ly}, adv. -- {In*tru"sive*ness}, n. [1913 Webster]