I. ə̇nˈfil.ˌtrāt, ˈin(ˌ)fil- also -_fəl-, usu -ād.+V verb
Etymology: in- (II) + filtrate
transitive verb
1. : to cause something (as a liquid) to enter by penetrating the interstices of
infiltrate tissue with a local anesthetic
2. : to pass into or through (a substance) by filtering or permeating
3. : to advance (troops) by sending single men or small groups through gaps or weak points in the enemy line
4. : to enter or become established in (as an organization) gradually or unobtrusively and in large numbers
parties which labor leaders accused of being … infiltrated by extreme nationalists — Clifton Daniel
intransitive verb
1. : to enter, permeate, or pass through a substance by filtering
many Hebrew idioms have infiltrated, in translated forms, into various Jewish dialects — William Chomsky
2. of troops : to advance or to enter a hostile area by proceeding singly or in small dispersed groups
tend rather to infiltrate to supply lines and rear installations — Cavalry Journal
II. noun
: something that infiltrates ; specifically : a substance that passes into the bodily tissues and forms an abnormal accumulation