spread or diffuse through; "An atmosphere of distrust has permeated this administration"; "music penetrated the entire building"; "His campaign was riddled with accusations and personal attacks"
march aggressively into another's territory by military force for the purposes of conquest and occupation; "Hitler invaded Poland on September 1, 1939"
penetrate or assault, in a harmful or injurious way; "The cancer had invaded her lungs"
occupy in large numbers or live on a host; "the Kudzu plant infests much of the South and is spreading to the North"
any large scale calamity (especially when thought to be sent by God)
any epidemic disease with a high death rate
a serious (sometimes fatal) infection of rodents caused by Yersinia pestis and accidentally transmitted to humans by the bite of a flea that has bitten an infected animal