fill in
"fill-in" is a 6-letter English headword indexed on PlainSpell.
The verdict
“fill in” is uncommon English (outside the top frequency list), classed as a verb. The kind of spelling people second-guess.
- Unranked
- below top-frequency English
- 7
- letters
According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - To fill; to replace material that is absent or has been removed.
Corpus desk
Index EN-fill-in · fill in · English
fill in · unranked · 0 variants · 0 confusables
- FREQ-UNRANKED Unranked
- LEN-LONG 7 letters
- VOW-2 2 vowels
- CONFUS-0 No pairs
- VAR-0 0 variants
- BOOK-THIN "F" thin
- PHOTO-UNK Peer pending
Read with this headword: Spelling guide for this pattern
Desk codes from Wiktionary headword shape, FrequencyWords rank tier, confusable-pair count, generated misspelling depth, letter-cohort book size, and photo-finish peer. Not a difficulty grade.
| Property | Value |
|---|---|
| Headword | fill in |
| Language | English |
| Part of speech | Verb |
| Letters | 7 |
| Misspellings tracked | 0 |
| Confusable pairs | 0 |
| Source | Wiktionary (kaikki.org) |
Long-tail rank of “fill in” in English
Rare enough to double-check
fill in is uncommon English outside the top frequency list, classed as averb. Rarity is why readers land here mid-draft. 5 senses are on record.
We couldn't generate a plausible misspelling set for fill in, which points to an orthography that plays by predictable English rules. Our confusable-pair dataset has no match for it, since nothing in our dataset looks or sounds close enough to cause mix-ups.
No borrowing history is documented for this entry, so its spelling is easiest explained by how it's pronounced rather than where it came from. The correct English form is fill in, spelled F-I-L-L- -I-N.
Definition
- 1To fill; to replace material that is absent or has been removed.
- 2To inform somebody, especially to supply someone missing or missed information.
- 3To substitute for somebody or something.
- 4To complete a form or questionnaire with requested information.
- 5To beat up; to physically assault.
Recorded use
Wiktionary examplesThese source excerpts show how fill in appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.
After you're done laying the pipe, fill in the trench.
The decking of the bridge consisted of steel troughing over an average clear span of 26 ft., the troughing being filled in with concrete to form the road surface.
This word in other languages
Definitions, pronunciation, and etymology for this entry are drawn from Wiktionary via the kaikki.org structured extract (CC BY-SA). See the methodology for how each field is sourced and updated.