infiltrate

/ˈɪnfɪlˌtreɪt/
verb
  1. To secretly enter or join a group, organization, or place in order to gain information or cause harm.
    • Undercover agents infiltrated the criminal gang to gather evidence.
    • Hackers tried to infiltrate the company's computer network.
    • The spy managed to infiltrate the enemy headquarters.
  2. To gradually spread into or through something, such as a liquid or idea.
    • Water began to infiltrate the basement through cracks in the foundation.
    • The smell of smoke infiltrated the entire house.
    • New technologies are infiltrating every aspect of our daily lives.
noun
  1. A person who secretly enters a group or place; a spy or undercover agent.
    • The security team identified the infiltrate during the routine check.
    • They suspected an infiltrate was leaking information to the press.
    • The infiltrate was discovered and expelled from the organization.