Infiltrate

How to spell infiltrate

10 letters · 3 syllables

How to pronounce infiltrate

Say the part in capitals loudest.

What does infiltrate mean?

1. verbTo enter or gain access to a place or organisation gradually and secretly, usually to gather information or cause harm.
2. verbTo pass or cause a liquid or substance to pass gradually through the pores or small gaps of something.

Infiltrate in a sentence

• The agent spent two years trying to infiltrate the smuggling network.

• Heavy rain caused water to infiltrate the cracked foundations.

• Hackers managed to infiltrate the company servers without being detected.

• The dye was left to infiltrate the fabric overnight.

Where does infiltrate come from?

Language of origin: Latin

This word was built in the mid-1700s from the Latin prefix in-, meaning 'into', and the Medieval Latin filtrum, which literally meant a piece of felt; because matted felt was used to strain and clean liquids, filtrum became the source of the word 'filter' as well. The original sense of 'infiltrate' was strictly physical: to cause a liquid to pass gradually through the small spaces in a porous substance, much as water seeps through felt or soil. From that slow, seeping action came the figurative military and political sense that dominates today, namely people quietly working their way into a place or group a few at a time. The fact that the modern spy meaning grew out of a plumbing-and-soil image is a useful reminder that the middle of the word is 'filtr', the same cluster found in 'filter', not 'filter-ate'. Knowing the felt-strainer ancestry helps fix the single l and the tr that learners often scramble.

How the word is built

• in- (into)
• filtr- (from Medieval Latin filtrum, felt used as a strainer)
• -ate (verb-forming suffix)