Fell swoop

A quick, decisive move.

I believe that the "fell" in question is the 'fierce' or 'lethal' fell, coming from the Old French fel. "Swoop", as we all know, means to make a sudden attack.

Thus, "In one fell swoop, I stepped through the door" would probably be inappropriate usage.

"In one fell swoop, I moved my queen to rook 4" is borderline.

If you are a serious user of the English language, you should probably save this for sentences like "In one fell swoop, we fell upon the Huns and tore them limb from limb"

So now you know.

MACDUFF

He has no children. All my pretty ones?
Did you say all? O hell-kite! All?
What, all my pretty chickens and their dam
At one fell swoop?

People tend to forget just how Great many Great Artists were in their day. Renaissance artists are misunderstood. Homer and Chaucer are disparaged. The old sounds of swing and soul comes across as trite, clichéd. But our perspective isn't the same as theirs. All of their work had that infectious new-car smell about it at one time - that scent that many of you crave, that you can only get now from Mark Leyner or Sigur Rós. These guys were once incredibly original, whiplash-inducingly original. The now-hackneyed diffuse light of a prime Vermeer once gave everyone the howling fantods.

Where am I going with this? Right to Shakespeare. You may not realize it, but he pretty much invented a large portion of modern English with his pen. Think of some words and phrases you use everyday - 'bloodstained', 'madcap', 'cold-blooded', heck, even 'gadzooks'. Shakespeare coined all of these and more - just one more example of what made him Great.

'One fell swoop' has to be one on the shortlist of his notable idiomatic achievements - lyrical and evocative while maintaining brevity. He dropped it in The Scottish Play, Act 4, Scene 3, right as he's winding up the motors of retribution in his characters. Never again would a Scotsman be so damned silver-tongued as in these acts*.

* Joking! I joke! Scotsmen are plenty eloquent! Please put the firearms down!

Also - according to the Word Detective, Tem42 is bang-on about the origins of fell - it does indeed come from the Old French fel, which is also the root word for felon. Bra-vo, Tem42!