A filter word sits between the reader and the moment, reporting a character’s experience instead of putting the reader inside it. She felt the cold. He saw the door open. I noticed she was crying. Grammatically fine. Structurally, each one adds a narrator filtering the sensation before the reader gets to it, instead of letting the reader have the sensation directly.

What Counts as a Filter Word

The usual suspects: felt, saw, heard, noticed, realised, wondered, watched, smelled, thought, knew. Any verb of perception or cognition that sits between a character and their own experience.

Filtered: She felt the cold seep through her coat. Direct: The cold seeped through her coat.

Filtered: He heard the door creak open behind him. Direct: The door creaked open behind him.

Filtered: I realised I’d left the stove on. Direct: The stove. I’d left it on.

The direct versions put the reader in the point-of-view character’s body rather than reporting what that body experienced, and they’re shorter too. In deep third or first person, where the whole point is that the reader is inside a specific consciousness, filter words undercut the effect you’re going for.

Why They’re Worth Cutting

Two reasons, and they compound.

They add distance you probably don’t want. If your point of view is close, deep third or first person, the reader should already be behind the character’s eyes. Telling them the character saw or felt something re-establishes a narrator that close narration is trying to get rid of.

They add words that do no work. She felt the cold is longer than the cold seeped through her coat and says less. Every filter word is an opportunity to either cut a word or replace it with something more specific.

Run a search for felt, saw, heard, noticed, realised, wondered, watched across a chapter and see what comes back. Cutting them tightens prose faster than almost any other single edit in a line pass.

When to Keep Them

Filter words exist for reasons, and cutting every single one can leave prose feeling oddly breathless.

Omniscient or distant narration. If your narrator is deliberately outside the character, reporting rather than inhabiting, filter words are doing the job they’re meant to do. A pulled-back narrator should feel like it’s reporting perception, not merging with it.

Genuine uncertainty. She thought she heard footsteps is different from footsteps sounded behind her. The filtered version signals doubt, she isn’t sure. If the uncertainty is the point, keep the filter.

Rhythm. Occasionally a filter word is simply the better-sounding sentence. Craft rules are tools, not laws. If cutting one makes a sentence worse, don’t cut it.

The real test: is this word doing anything a direct version wouldn’t do better? For filter words specifically, that’s a hard bar to clear.

How to Find Them

Search your manuscript for the common ones directly: felt, saw, heard, noticed, realised, wondered, watched, smelled. It’s tedious but exhaustive, and it catches everything.

Writing Desk tip: The AI Editor’s line edit lens flags filter words as part of its chapter-by-chapter feedback, alongside passive constructions and adverbs, so you’re not relying on memory for which words to search. It highlights the specific lines, you decide what to do with each one.