Filter words remind the reader that they’re being told a story rather than allowing them to experience the highs and lows of the the point-of-view character‘s life. We therefore need to remove all instances of these, unless they help the story progress. Examples of filter words include:
- became
- felt
- found him/herself
- realised
- seemed
- sensed
- thought
- wondered
Compare (1) and (2).
- Sam saw Phil and Dan across the road. She wondered what they were laughing at.
- Sam saw Phil and Dan across the road. What were they laughing at?
Example (1) is flat. It doesn’t engage the reader, who is left watching the action as if through a photographic filter. Example (2) has the reader right inside Sam’s head, following along with her internal monologue, represented by free indirect speech. The reader is engaged and is curious about what Phil and Dan are laughing at.
Example (1) tells the reader what Sam is thinking. Example (2) shows the reader what she is thinking. By the infamous writing adage ‘show, don’t tell’, (2) is superior to (1).

How to remove filter words
To remove filter words, it’s often possible to do no more than delete them from the sentence, sometimes with a minor modification of the syntax as in (1) and (2) above. Other times, you might need to make bigger changes, including removing a whole sentence. You’ll be left with narrative that keeps the reader in the story rather than outside looking in.