knock someone over with a feather

present singular third person knocks someone over with a feather · participle present knocking someone over with a feather · participle past knocked someone over with a feather · past knocked someone over with a feather · alternative knock someone down with a feather

1. excessiveidiomaticinformalTo greatly surprise or astonish someone.

   She hardly, she said, believed her own senses. You might have knocked her down with a feather. She did not know whether she stood on her head or her heels.

   1838 February 17, “Review of Books. Hood’s Own. No. 1. Baily.”, in The Idler, and Breakfast-table Companion; a New and Fashionable Weekly Journal of Literature, Fine Arts, Music, Amusement, Exhibitions, Varieties, Satire, and the Stage, volume II, numbers 7 (nos. 50 and 51), London: Published for the proprietor by George Denney, at the office, 7, Tavistock Street, Covent Garden, →OCLC, page 50, column 2

   3 more examples

   "I thought you might see what she's up to if she is up to something, and I'm pretty sure she is." / "You could knock me over with a feather," Jane said. "Well! Yes, it does sound as though she's up to something I'd be inclined to say. But you can't be sure with an odd one like Sue. Might be a touch of harmless craziness."

   1977, Joe Ashby Porter, chapter 50, in Eelgrass (A New Directions Book [New Directions Paperbook]; [438]), New York, N.Y.: New Directions Publishing, →ISBN, pages 102–103

   Fat cat art collectors shelled out thousands of dollars for works by a popular new painter named DaVinci, and hoity-toity critics called him the king of the canvas – till the world learned that DaVinci is a duck! […] "And when all those snooty people found out they'd been bamboozled by a bird, you could have knocked them over with a feather."

   1990 November 27, Laurel Bowie, quoting Ossie Martins, “That’s just ducky!: Artist exposed as a QUACK!”, in Weekly World News, number 18259, New York, N.Y.: American Media, Inc., →ISSN, →OCLC, page 24

   Reflecting on being told he was to referee the 1991 World Cup final, the former flanker [Derek Bevan] told Radio Wales, "I couldn't believe it. They talk about knocking you over with a feather, I was in a dream for the rest of the day.[…]"

   2016 May 8, Simon Thomas, “Bevan blows the whistle for full time on officiating career”, in Wales on Sunday