Filter words are verbs of perception and cognition that insert themselves between the reader and the scene: saw, heard, felt, thought, noticed, realised, seemed. Instead of showing the world, a filtered sentence shows a character receiving the world. “Anna saw that the door was open” describes an act of looking. “The door was open” describes the door. Nine times out of ten, the door was the point.
The term comes from Janet Burroway, whose Writing Fiction is one of the most widely used creative writing textbooks in the English-speaking world. Burroway called a filter any word that reminds the reader there is an observer standing between them and the event. The trouble is that filters are invisible to the person who wrote them. They are not grammatical errors, no proofreader will flag them, and each individual sentence sounds perfectly fine. They do damage only in bulk, and bulk is something you can only see when somebody counts.
What filter words are and how they work
The mechanism is easiest to see in a pair of sentences describing the same event:
Mark heard the floorboards creak upstairs. He felt his heart begin to beat faster.
Upstairs, the floorboards creaked. His heart beat faster.
The first version is a third longer and half as strong. Every event has been given a middleman: we do not hear the creak, we watch Mark hearing it. We do not feel the racing pulse, we note that Mark felt it. The reader, instead of standing in the dark house, stands next to the protagonist and observes his nervous system.
This is exactly the distance John Gardner wrote about in The Art of Fiction under the name psychic distance: prose can hold the reader far from a character or let them all the way inside their head, and the choice between the two should be deliberate. Filters shift the distance towards “far” without the author’s knowledge. You write a scene meant to be intimate and airless, and the syntax quietly pulls the camera back to a wide shot.
The list of suspects is short enough to memorise: saw, looked, watched, noticed, spotted, heard, felt, thought, realised, understood, knew, wondered, seemed, appeared, it occurred to her, she was aware that. Add to that the constructions “watched as” and “saw how”, which turn every action into a report about watching an action.
Why filters ruin a close point of view
Most contemporary genre fiction is written in close third person: the narration runs from inside one character, through their eyes and in their language. We cover this in more depth in our guide to point of view in a novel. In that convention, filters are not just unnecessary; they logically contradict the contract you have signed with the reader.
The contract says: everything on the page is what the character sees, hears and thinks. If so, then “she noticed that the man had a scar above his eyebrow” duplicates information. The mere fact that the scar appears in the narration means she noticed it. How else would it have got onto the page? The filter communicates something the convention settled long ago, and every duplicated piece of information is dead weight the reader must read without getting anything back.
There is a second, subtler cost. Filters almost always drag weak syntax behind them: a subordinate clause with “that” or “as”, a perception verb sitting in the main clause, and the actual event demoted to the subordinate one. The grammatical centre of gravity lands on looking and listening, activities that in fiction are background, never substance. Over a few hundred pages this syntactic pattern becomes audible, like a creaking chair: the reader cannot name the cause, but they can feel the prose has been watered down.
When a filter word is the right choice
Like every craft tool, filters have uses in which they are the best option. Hunting them to extinction is the same mistake we described in our piece on passive voice in prose: a helpful guideline promoted to dogma.
A filter earns its place when the act of perception is itself the event. “Only now did she notice that his suitcase was gone” says something different from “The suitcase was gone”: the point is the lateness of the noticing, the fact that she should have seen it earlier. Likewise, “he heard her before he saw her” describes an order of senses that is the substance of the scene. In sentences like these the perception verb carries information rather than syntactic ballast.
Filters are also useful when shifting distance. Opening a chapter from a wide shot, entering a new character’s head, a moment of disorientation after a blackout: there, briefly underlining that someone is looking and listening helps the reader work out whose eyes they are borrowing. Finally, first-person narration with a strong voice tolerates far more filtering, because a talkative narrator reporting their own impressions is part of the stylisation.
The practical rule: a filter stays if removing it costs the sentence information. If it only costs words, they were words you could afford to lose.
How to find filter words in your own manuscript
You cannot see filters in your own text, and it is not a matter of diligence. The writer knows the scene from the inside, so their brain reads intention, not syntax. What you need is a mechanical pass that does not trust impressions.
- Make a list and search for it. Searching for “saw”, “heard”, “felt”, “thought”, “noticed”, “realised”, “seemed”, “watched” will catch most occurrences. It is fifteen minutes of work per chapter.
- Judge density, not individual sentences. Three filters per chapter are not a problem. Three filters per page in a scene that is supposed to grip by the throat are. The most damage happens in clusters inside tense scenes, where every middleman between reader and event costs the most. We wrote about how tension is distributed across a chapter in our piece on pacing in a novel.
- Rewrite from the event. Instead of deleting the filter from the old sentence, write a new one that starts with what happened: the floorboards creaked, the light went out, a scar cut across his eyebrow. Leave the perceiving to the point-of-view convention; it handles it for free.
- Check what the filter was hiding. A frequent discovery: after removing “she felt sadness wash over her” you are left with “sadness washed over her”, an abstraction without an image. The filter was masking the fact that the emotion was never shown at all. That is where the real work begins, and it is the work described in our guide to building characters.
- Leave the deliberate exceptions alone. Perception as event, a shift in distance, a narrator’s voice: those sentences have defended their filter. Do not cut them just because the list told you to.
This pass belongs to the self-editing stage, after the structural questions are settled and before the sentence-level polish. The full order of operations is in our guide on how to edit a novel.
Filters belong to a larger family
Filter words are one branch of a wider class of constructions that weaken prose not by error but by dilution: passive voice where active would hit harder, weak verbs propped up by adverbs, repetitions the author’s ear has stopped hearing. Each of these on its own is a trifle. Together they decide whether prose reads dense or watery, and they share one property: they are invisible in your own text, because you read your intention instead of your words.
That is why this stage of editing benefits from measurement. Vellam’s static analysis marks weak verbs, repetitions, passive voice and adverb density in the text, layer by layer, chapter by chapter. You get a map of clusters instead of a general impression, and the decision about which sentence to rewrite and which to keep stays yours. You can look at sample analyses run on excerpts from a real novel.
Frequently asked questions
What are filter words in fiction?
Filter words are verbs of perception and cognition that report the receiving of an event rather than the event itself: saw, heard, felt, thought, noticed, realised, seemed. They insert an observer between the reader and the scene and increase narrative distance, usually against the author’s intention.
Are filter words a grammatical error?
No. A filtered sentence is grammatically and stylistically correct. Filters do damage only in bulk, because they duplicate information the point-of-view convention already conveys and push the actual events into subordinate clauses. It is a question of strength, not correctness.
When should you keep a filter word?
When the act of perception is itself the substance of the scene: a character notices something too late, hears something before seeing it, works something out gradually. A filter is also justified when shifting narrative distance, and in first-person narration with a strongly stylised, talkative voice. The test: if removing the filter costs the sentence information, the filter stays.
How do you find filter words in your own text?
Mechanically, not by feel. Search the manuscript for the most common perception verbs (saw, heard, felt, thought, noticed, realised, seemed, watched) and judge density per scene rather than individual sentences. Clusters inside tense scenes do the most damage. Static text-analysis tools can show such clusters on a map of the whole chapter.
How are filter words different from “show, don’t tell”?
They are related but distinct. “Show, don’t tell” is about the choice between scene and summary. Filtering is a narrower syntactic phenomenon: even inside a fully dramatised scene, individual sentences can report perception instead of showing the event. You can write scenically and still filter, which is why both are worth checking separately.