From WordNet (r) 2.0 (August 2003) [wn]:
invasive
adj 1: relating to a technique in which the body is entered by
puncture or incision [ant: noninvasive]
2: marked by a tendency to spread especially into healthy
tissue; "invasive cancer cells" [ant: confined]
3: involving invasion or aggressive attack; "invasive war"
[syn: incursive, invading]
4: gradually intrusive without right or permission; "we moved
back from the encroaching tide"; "invasive tourists";
"trespassing hunters" [syn: {encroaching(a)},
{trespassing(a)}]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Invasive \In*va"sive\, a. [LL. invasivus: cf. F. invasif. See
Invade.]
1. Tending to invade; characterized by invasion; aggressive.
"Invasive war." --Hoole.
[1913 Webster]
2. (Med.) tending to spread, especially tending to intrude
into healthy tissue; -- used mostly of tumors. [Narrower
terms: malignant] PJC]