fatten up

verb

By · According to Wiktionary data (CC BY-SA) ·

"fatten-up" is a 8-letter English headword indexed on PlainSpell.

The verdict

“fatten up” is outside the top-ranked English vocabulary, used as a verb - the kind of word writers most often double-check.

Unranked
below top-frequency English
9
letters

According to Wiktionary data (CC BY-SA, analyzed May 6, 2026) - To cause to gain weight by means of feeding.

Key facts for fatten up
PropertyValue
Headwordfatten up
LanguageEnglish
Part of speechVerb
Letters9
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Where “fatten up” sits in English frequency

fatten up falls outside the top-100,000 ranked English words, the long-tail zone of technical, archaic, or low-frequency vocabulary, exactly where readers second-guess spellings most.

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

Spelling & Dictionary Insight

The English entry for fatten up is 9 letters long, classified as a verb. It sits outside the most-frequent rank tiers, which is often why uncommon words generate more spelling variants per reader. Wiktionary records 3 distinct senses for this headword, so context determines which meaning a reader should apply.

Our edit-distance generator produced no likely misspellings for fatten up, suggesting the orthography follows predictable English patterns. Our dataset records no confusable match here, which typically means the spelling is too distinctive to be mistaken for another word.

No borrowing history is documented for this entry, so its spelling is easiest to reason about phoneme by phoneme, absent a documented history. The correct English form is fatten up, spelled F-A-T-T-E-N- -U-P.

Definition

  1. 1
    To cause to gain weight by means of feeding.
  2. 2
    To become fat or fatter by gaining weight.
  3. 3
    To make bigger; to expand.

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 "fatten up"?
"fatten up" is spelled F-A-T-T-E-N- -U-P.
What does "fatten up" mean?
As a verb, "fatten up" means: To cause to gain weight by means of feeding.
What language does "fatten up" come from?
"fatten up" is a English word. You can look up definitions, pronunciations, and spelling data for this and other words across English, Spanish, Portuguese, French, and German on PlainSpell.
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.

Using “fatten up”

The practical upshot for anyone who landed here from a spell-check.

  • The one correct English spelling is F-A-T-T-E-N- -U-P - every other letter order is a misspelling in standard orthography.
  • Browse more English words and confusable pairs in the same reference. English words
Data Source

Wiktionary (via kaikki.org), licensed under CC BY-SA & GFDL. Word ordering uses an open word-frequency list; misspelling variants are generated by edit-distance from the correct headword.

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

Source: FrequencyWords open word-frequency list FrequencyWords open word-frequency list