WordWeb Online

1. Cause (a liquid) to enter by penetrating the interstices
    
2. Enter a group or organization in order to spy on the members
   "The student organization was infiltrated by a traitor";
   - penetrate
    
3. Pass into or through by filtering or permeating
   "the substance infiltrated the material"
    
4. Pass through an enemy line; in a military conflict
   - pass through

Derived forms: infiltrated, infiltrates, infiltrating

Type of: fall in, filter, get together, join, pass, percolate, permeate, sink in

Encyclopedia: Infiltrate