Definition of "infiltrate"

infiltrate

/ˈɪnfɪltɹeɪt/

verb
third-person singular simple present infiltrates, present participle infiltrating, simple past and past participle infiltrated
1. (transitive, intransitive) To surreptitiously penetrate, enter or gain access to.
2. (transitive) To cause to penetrate in this way.
3. (transitive, intransitive, of a liquid) To pass through something by filtration.
4. (transitive) To cause (a liquid) to pass through something by filtration.
5. (transitive, intransitive, medicine) To invade or penetrate a tissue or organ.
6. (transitive, military) To send (soldiers, spies, etc.) through gaps in the enemy line.
7. (intransitive, of an intravenous needle) To move from a vein, remaining in the body.
noun
plural infiltrates
1. (pathology) Any undesirable substance or group of cells that has made its way into part of the body.
  Quotations
  One critical distinction to make is whether a focal corneal infiltrate is infected with bacteria or is a sterile immunologic response.
  2008, Jimmy D. Bartlett, Siret D. Jaanus, Clinical Ocular Pharmacology, page 539