One Fell Swoop...
Learn English member +Yanti Vijaya
asked about this idiom:
"in one fell swoop"? I found it in today's news: "But in one fell swoop, the mission has enormously expanded our view of the Galaxy."
First, a little history. This is not the ordinary meaning of the word "fell (fall)" as in "He fell down the stairs." This is an older, literacy meaning, where "fell" is an adjective meaning "evil and frightful." The word "fell" here is related to "felon" (a person who has committed an evil crime). It's all an extended meaning of "fall down" with the figurative sense of "down" meaning "evil or sinful, low or base," etc.
"Swoop" is a fast motion, usually downward and through the air, and usually in order to snatch prey. So we would say, "The owl swooped down and grabbed the mouse."
Put together, for something to happen in "one fell swoop" meant that SOMETHING BAD or destructive happened SUDDENLY.
That is the original meaning. But now, many years later, "one fell swoop" is often used to simply mean "all of a sudden" or to be done "in one action." It does not always have the idea of being something evil or destructive.
So we might say:
"Their army destroyed our forces in one fell swoop." (the historical meaning)
"I'm not working on the new project this morning. I will finish the editing of both projects tonight in one fell swoop." (the newer meaning)