infiltrate
in.fil.trate \in-'fil-.tra-t, 'in-(.)fil-\ \.in-(.)fil-'tra--sh*n\ \'in-(.)fil-.tra-t-iv, in-'fil-tr*t-\ \-.tra-t-*r\ vt 1: to cause something (as a liquid) to enter by penetrating the interstice s of 2: to pass into or through by filtering or permeating 3: to pass (troops) singly or in small groups through gaps in the enemy li ne 4: to enter or become established in gradually or unobtrusively : to enter, permeate, or pass through a substance or area of filtering - in.fil.tra.tion n