The act of secretly entering a physical location and/or organization.
The substance which has entered the pores or cavities of a body.
process by which water on the ground surface enters the soil.
The act or process of infiltrating, as of water into a porous substance, or of a fluid into the cells of an organ or part of the body.
The action of irrupting or breaking into; a violent entry or invasion; an inbreaking; an intrusion.
An abrupt increase in the size of a movement or organization.
An abrupt increase of an animal population.