Part of speech: Verb
pass through an enemy line
Example: in a military conflict
Part of speech: Verb
pass into or through by filtering or permeating
Example: the substance infiltrated the material
Part of speech: Verb
cause (a liquid) to enter by penetrating the interstices
Part of speech: Verb
enter a group or organization in order to spy on the members
Example: The student organization was infiltrated by a traitor
Penetrate, Infiltrate, Pass through