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1. To use a filtration device or system to remove something from something else. A noun or pronoun can be used between "filter" and "out." These noise-canceling headphones were great at filtering all the background noise out during my flight to New York. We can use this machine to filter out anything that might pollute the water sample.
2. To keep something from being known or experienced. A noun or pronoun can be used between "filter" and "out." Your job is to scan the user forum and filter out any offensive posts. You can't just filter negative feedback out from the "Reviews" page. Customers deserve to see the whole picture!
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
To prevent something from passing through, being communicated, or being perceived: My new glasses filter out ultraviolet rays. These headphones filter unwanted noise out.
The American Heritage® Dictionary of Phrasal Verbs. Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.