adj.
 tending to invade or intrude. 
▸tending to spread very quickly and harmfully.
 ▸(of medical procedures) involving the introduction of instruments or other objects into the body or body cavities.
 
  Derivative
  
  Etymology
  ME: from obs. Fr. invasif, -ive or med. L. invasivus, from L. invadere (see invade).