What does eff mean?
'Eff' is a euphemism built directly on the initial letter of one of English's strongest taboo words. As a verb, it means either to utter that obscenity — as in 'effing and blinding', a chiefly British phrase for furious swearing — or, more delicately, to have sexual intercourse. Because it merely names the letter F, it lets speakers gesture at the offensive word without pronouncing it, which makes it useful in broadcast contexts, family conversation, and print where the original would be censored. The word is informal and mildly comic in tone; it softens rather than eliminates the profanity, so it remains out of place in formal registers. Its derived forms include 'effing' and 'effed', which function much like the inflections of the word they replace. For learners, 'eff' is worth knowing mainly as a marker of register: encountering it signals casual, often heated speech, and using it signals an awareness that some words are better spelled than said.
A euphemistic substitute for the vulgar verb 'fuck': to use such language, or (transitive) to have sexual intercourse.
"Stop effing about and get the job done."
Chiefly informal; the phrase 'eff and blind' is especially British.
An instance of swearing with the word 'fuck'; a euphemistic reference to it.
"The script had a few effs in it, all bleeped for broadcast."
Used only for the rare noun sense referring to instances or utterances of the word.
"The transcript recorded three effs before the microphone was cut."
It's the polite way to say the impolite word — 'eff' literally spells out just the first letter of its taboo original.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of eff
'Eff' arose as a phonetic spelling of the name of the letter F, the first letter of the obscene verb it stands in for. Such letter-based euphemisms developed naturally in spoken English as speakers sought ways to refer to taboo language without repeating it. It has no deeper etymological root of its own, being purely a spelling-based derivative, and it gained wider currency through twentieth-century British colloquial speech.
Related word forms
How eff is actually used
Informal and colloquial throughout; it exists precisely because speakers want a milder stand-in for a strong obscenity. It is common in British English, especially in the phrase 'eff and blind', but understood in most varieties of English. Still inappropriate in formal writing or polite company, though markedly less offensive than the word it replaces.