What does fatso mean?
Fatso is a contemptuous nickname for a person considered overweight, formed in English by adding the jocular suffix '-o' to the everyday word 'fat'. It belongs to a distinctly informal, mocking register, alongside coinages like 'weirdo' and 'wino', and it functions almost exclusively as an insult: calling someone a fatso is body-shaming and is very likely to cause offence. The word appears most often today in fiction, dialogue, and older comedy, where characters trade playground-style taunts, and in reported speech describing such exchanges. Its plural is commonly given as either 'fatsos' or 'fatsoes'. While linguistically interesting as an example of English's playful suffixing habits, it offers little value beyond recognising the insult when encountered; writers aiming for neutral description of body size should avoid it entirely in favour of respectful language.
nounA derogatory name for a fat person, used as an insulting nickname.
- An insulting or mocking nickname for someone regarded as fat.
"The schoolyard bully sneered and called him a fatso."
""Get lost, fatso," he shouted across the playground."
"In the old comedy films, the skinny character's jibes at his fatso sidekick now read as casual cruelty."
Both plurals are accepted; 'fatsos' with simple -s is common, while 'fatsoes' inserts the usual -e- before -s seen in words like 'tomatoes'.
"The film's villains were a pair of sneering fatsos."
'Fatso' is part of a whole family of English insults built by slapping a mock-Italian '-o' onto an ordinary word — think 'weirdo' and 'winos'.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of fatso
'Fatso' is an English formation combining the native Germanic word 'fat' — from Old English 'fætt', meaning fattened or plump — with the jocular suffix '-o', popularised in nineteenth- and twentieth-century English for nicknames and mocking labels, as in 'weirdo' and 'richo'-style coinages. Its closest cognates are thus other English '-o' mock-names rather than words in other languages; the underlying root is shared with English derivatives of 'fat' such as 'fattening' and 'fatness'. The precise date of first recorded use is uncertain, but the word belongs broadly to modern colloquial English.
How fatso is actually used
Strongly informal and pejorative — using it of a real person is body-shaming and likely to cause offence. It survives mostly in fiction, comedy, and reported speech rather than polite conversation.
Easily confused with fatso
A fatwa is a formal Islamic legal ruling or decree, entirely unrelated to 'fatso', an insulting nickname for a fat person.