fill up

verb

"fill-up" is a 6-letter English headword indexed on PlainSpell.

The verdict

“fill up” 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 make (something) completely full.

Corpus desk

Index EN-fill-up · fill up · English

fill up · 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.

Key facts for fill up
PropertyValue
Headwordfill up
LanguageEnglish
Part of speechVerb
Letters7
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “fill up” in English

fill upranks outside the top 100,000 English headwords, in the long tail of specialist, archaic, or seldom-used vocabulary, exactly the territory where a reader stops mid-sentence to double-check spelling.

Beyond rank #100,000. Source: FrequencyWords open word-frequency list.

Rare enough to double-check

fill up is uncommon English outside the top frequency list, classed as averb. Rarity is why readers land here mid-draft. 10 senses are on record.

We couldn't generate a plausible misspelling set for fill up, and the word's spelling is regular enough that our generator found nothing worth flagging. It is not paired with a close-neighbour confusable in our dataset, which usually means its spelling is distinct enough that readers don't reach for a similar-looking word instead.

No documented word history exists for this headword, so its spelling is best read as a straightforward mapping from sound to letter. The correct English form is fill up, spelled F-I-L-L- -U-P.

Definition

  1. 1
    To make (something) completely full.
  2. 2
    To fill the tank of a vehicle with fuel.
  3. 3
    To become completely full.
  4. 4
    To become tearful as a result of strong emotion.
  5. 5
    To annoy, or displease, by taunting, or by excessive nagging.
  6. 6
    To satisfy the hunger of (someone).
  7. 7
    To satisfy one's hunger; to stop being hungry.
  8. 8
    To make a full house on the turn or the river.
  9. 9
    To fill in / fill out a form etc.
  10. 10
    To make complete, to bring to a full development.

Recorded use

Wiktionary examples

These source excerpts show how fill up appears in context. They illustrate usage; the definition above remains the entry’s reference meaning.

  1. It costs a fortune these days to fill up.
  2. "Game over," Waddicor warns. "Look at the fuel gauge. Someone's forgotten to fill up." The heavily laden train has come from Freightliner's Maritime Terminal in Southampton's western docks. Waddicor reckons there might not be enough diesel in the tank to complete the journey.

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.

Frequently Asked Questions

How do you spell "fill up"?
"fill up" is spelled F-I-L-L- -U-P.
What does "fill up" mean?
As a verb, "fill up" means: To make (something) completely full.
What language does "fill up" come from?
"fill up" is a English word. PlainSpell covers definitions, pronunciations, and spelling data across English, Spanish, Portuguese, French, and German.
Is PlainSpell free to use?
Yes, PlainSpell is a completely free word reference. You can look up definitions, pronunciations, confusable pairs, homophones, and spelling corrections across 5 languages without any sign-up or subscription.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list