If someone makes a ridiculous remark about your risible muscles, they are not necessarily deriding your physique. Risible can also mean "associated with laughter," so risible muscles can simply be the ones used for laughing. (You've also got a set of risorius muscles around your mouth that help you smile.) Next time you find something laughable, tip your hat to ridēre, the Latin verb meaning "to laugh" that gave us risible as well as ridiculous and deride.
The suggestion was downright risible. a risible comment that made the whole class laugh
Recent Examples on the WebNow, onto the more risible argument: that Amazon’s acquisition represents a major invasion of consumer privacy. Jacob Carpenter, Fortune, 8 Aug. 2022 His legions of critics, however, have found that excuse risible. Andy Meek, BGR, 12 July 2022 Even without Bobulinski’s contradictory account, that assertion was already risible given the mounting evidence that, while vice president, Biden met with some of Hunter’s associates from China, Ukraine, Mexico, and elsewhere. The Editors, National Review, 18 July 2022 The idea that Fox News is the only news organization that takes advantage of the First Amendment is risible. Erik Wemple, Washington Post, 7 July 2022 The idea of spending that much on a device designed to go no farther than my spare bedroom might have seemed risible a few years ago. Tom Vanderbilt, Outside Online, 14 Mar. 2020 The idea should be absurd, risible, farcical, outré. Charles C. W. Cooke, National Review, 15 Mar. 2022 Mei draws her crush as a merman—a fantasy more risible than racy. Shirley Li, The Atlantic, 25 Mar. 2022 These were completely risible statements such as the one claiming that Ukraine is a fascist, anti-semitic State... Rica Cerbarano, Vogue, 22 Mar. 2022 See More
Word History
Etymology
Late Latin risibilis, from Latin risus, past participle of ridēre to laugh