Definition of Eff

Verb: eff ef
Usage: Brit

[Brit, vulgar] Have sexual intercourse
- sleep together, love, make out, make love, sleep with, have sex, know [archaic], do it, be intimate, have intercourse, lie with [archaic], bed, have a go at it, get it on, make whoopee, nail [N. Amer]
Utter obscenities or profanities
"The drunken men were effing loudly in the street";
- curse, cuss, blaspheme, swear, imprecate, eff and blind [Brit]