UK slang term to describe one who is shouting in annoyance, using a generous amount of swearwords - with particular reference to the word 'fuck' - in the process.

'Eff' - being the pronunciation of the letter 'F' - is, as you might guess, a polite euphamism for saying 'fuck' outright. A moderately safe and useful replacement for such a word in the presence of, say, children or the local parish vicar.

"I've never seen him so mad. He came round 'ere, effin' and blindin' and with the kids within earshot too."

Sometimes known as 'Effing and jeffing'. Similar also to:

Turn the air blue.
Swear like a trooper.