fatten up

verb

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

The verdict

“fatten 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
9
letters

According to Wiktionary data (CC BY-SA, analyzed September 3, 2026) - To cause to gain weight by means of feeding.

Corpus desk

Index EN-fatten-up · fatten up · English

fatten up · unranked · 0 variants · 0 confusables

  • FREQ-UNRANKED Unranked
  • LEN-LONG 9 letters
  • VOW-3 3 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 fatten up
PropertyValue
Headwordfatten up
LanguageEnglish
Part of speechVerb
Letters9
Misspellings tracked0
Confusable pairs0
SourceWiktionary (kaikki.org)

Long-tail rank of “fatten up” in English

fatten 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

fatten up is uncommon English outside the top frequency list, classed as averb. Rarity is why readers land here mid-draft. 3 senses are on record.

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.

Recorded use

Wiktionary examples

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

  1. My cat looks underweight, so I'll fatten him up with higher-calorie cat food.
  2. I visited my mother for a month, and she managed to fatten me up 20 pounds.

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.

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

Source: FrequencyWords open word-frequency list