infiltrate

Verb

• pass through an enemy line; in a military conflict

• pass into or through by filtering or permeating
  • the substance infiltrated the material
    

• enter a group or organization in order to spy on the members
  • The student organization was infiltrated by a traitor
    

• cause (a liquid) to enter by penetrating the interstices

Related words

• Synonyms: 
  pass through , penetrate