eff
verb (used with or without object)
fuck.
eff
1 American
[ef]
/ ɛf /
verb (used with or without object)
noun
verb phrase
eff.
2
American
abbreviation
-
efficient, efficiency.
-
effective, effectiveness.
eff
British
/ ɛf /
verb
-
taboo euphemism for fuck
eff off
-
slang to use obscene language
Other Word Forms
Etymology
Origin of eff
1940–45; euphemism for fuck, with eff as spelled form of the name of the initial letter
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
EFF leader Julius Malema hailed Friday's ruling, saying: "We are happy our Constitution has won."
From Barron's • May 8, 2026
The EFF instead endorses robust data privacy legislation that better informs users of what information they’re often unintentionally giving away when they agree to Big Tech’s terms and conditions.
From Salon • Apr. 16, 2026
The San Francisco-based privacy and civil rights advocacy organization, also known as EFF, mapped out more than 40 hidden license plate readers in Southern California, most of them along border roadways.
From Los Angeles Times • Feb. 28, 2026
My first day on the job at EFF literally was going to something called the Broadcast Protection Discussion Group.
From Slate • Oct. 13, 2025
These boxes are addressed to Gerard Van der Leun, EFF's Director of Communications, who will shortly mail those magazines to every member of the EFF.
From The Hacker Crackdown, law and disorder on the electronic frontier by Sterling, Bruce
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
