infiltrate into (something)
To pervade or pass through a particular place or thing. Blackout curtains, man. That's the only way to keep the morning sun from infiltrating into your room.
infiltrate (something)
To surreptitiously gain access to a particular group or thing, as to monitor or affect their activities. The boss is starting to wonder if an undercover cop has infiltrated our group.
infiltrate into something
1. to permeate something; to filter into something. Thesoursmell infiltrated into everything in the refrigerator. The paint smell infiltrated into every room in the house.
2. and infiltrate something to penetrate a group, secretly, for the purposes of spying or influencing the activities of the group. The spy infiltrated into the enemy headquarters. They infiltrated into the government.