Is "faff" well understood outside Britain?

Solution 1:

It appears the expression is still mainly a British one:

From the Phrase Finder:

  • Faffing about' is a phrase that is most often heard in the UK rather than in other parts of the English-speaking world. In fact, even in the UK it is something of an anachronism, more at home in a P G Wodehouse story than as 21st century street slang.

From World Wide Words:

  • It’s originally British, informal but not rude, and moderately common, especially in the form to faff about. The Daily Telegraph included this on 15 March 2008: “The early boarders certainly bag their seats quickly, but then they immediately relax and happily faff about putting their things in the overhead locker, generally getting in the way of the other passengers.

  • The word started to move into the wider language in its modern sense around the end of the nineteenth century, though it didn’t much appear in print until the 1980s.

Fom Wiktionary:

  • (Britain, slang) To waste time on an unproductive activity.
    • She faffed about so much, she never got to eat her breakfast.
    • I decided to stop faffing about and get some work done.

From One-off Britishisms:

  • “The Ben Wyatt I know, I don’t think he’d be happy just sitting here faffing around.”

  • The Britishism in there is derived from faff, a verb meaning dither or fuss, and is usually followed by about. The Oxford English Dictionary’s first citation, from an 1874 volume called Yorkshire Oddities, suggests that it originated as a regionalism: “T’ clock~maker‥fizzled an’ faff’d aboot her, but nivver did her a farthing’s worth o’ good.”

  • Up till now, U.S. use has been spotty (and I don’t mean spotty in the English sense). It is a favorite of New York Times sports blogger Jeff Z. Klein, who, covering the 2008 women’s soccer matches at the 2008 Olympics, wrote:

    • Much faffing about as these final minutes tick down. New Zealand have a throw. in deep in the Amerk zone, but the one Fern is surrounded by four Americans and winds up on her back as they run away with the ball.
  • Klein’s use of the plural verb have with the collective New Zealand indicates he has absorbed a bit too much English football coverage, and suggests that faff is still more or less a one-off.

As noted by a few users, the expression appears to be commonly used in Australia where it may have found its way in the early days as suggested the Phrase Finder:

From "The Australian Journal", 1879:

  • "No, it [a candle] burns quite steadily now; you are right about it faffing about before, because it blew towards my face."

  • Baring-Gould's citation locates the phrase amongst the rural working classes and its use in Australia at a time when English speakers in that country were predominantly ex-UK convicts, suggests that the phrase was to be found below rather than above stairs.

Solution 2:

I would say it's somewhat common here in Australia (although I am British).

It certainly has a lot of results on Google search of Australian websites, such as this gem on the 'achievements' of our Great Prime Minister:

http://www.afr.com/opinion/editorials/mr-turnbull-has-to-stop-faffing-around-20160310-gng85i

Note, this is not a .com.au website, but AFR = Australian Financial Review.