Prose craft
Deep POV
Third-person narration written from inside the character's conscious mind: no narrative distance and no filter words.
Deep POV (deep limited third person) presses close third to its floor: the narration "takes place within the character's conscious mind," perceiving only what the character perceives. Craft guidance (Tiffany Yates Martin, on Jane Friedman's site) prescribes "no filter words," cutting constructions like "she saw" or "he felt" so the reader "experiences the event as it happens"; the aim is "virtually no narrative distance" between reader and character.
Deep POV is the default register of much contemporary commercial fiction because it maximizes immersion, and it sharpens show, don't tell by removing the reporting layer. Its cost is confinement: the narration cannot know anything the viewpoint character misses, and sustaining a colored voice for hundreds of thousands of words is real work. The wide-ranging alternative is the omniscient narrator.