flex

Etymology

Latin flexus, past participle of flecto (“to bend”).

noun

1. (uncountable) Flexibility, pliancy.
2. (countable) An act of flexing.
   The hills become more rounded. The slopes are either the stooped shoulders of an aging colossus or the muscular flexes of a geologic youngster, but they are pleasant, comforting. This landscape is what most would think of […] 2002, Gary Noy, Red Dirt: A Journey of Discovery in the Landscape of Imagination, California's Gold Country, iUniverse, page 144
3. (uncountable, chiefly Britain) Any flexible insulated electrical wiring.
4. (uncountable) Flexible ductwork, typically flexible plastic over a metal wire coil to shape a tube.
   Flex is quick and cheaper to install than metallic systems, but it yields higher pressure loss than other types of ducts and requires runs of less than 15 feet, minimal turns and elimination of kinks. 2010, Aaron Lubeck, Green Restorations: Sustainable Building and Historic Homes, page 221
5. (countable, geometry) A point of inflection.
6. (countable, slang) The act of flaunting something; something one considers impressive.
   Getting together with other power players at Masa is the ultimate flex of conspicuous consumption. […] A party of five or more requires a deposit of $200 per person at least one week prior to the reservation. 2017, "Mogul Bites", Black American Moguls, Fall 2017, page 6
   It's an achievement to stand out from other Marvel movies in terms of special effects, but this whole movie feels like a flex for those computer wizards. 2019, Seth Sommerfeld, "Worldwide Web", Inlander, 4 July 2019 - 10 July 2019, page 37
   6 March 2020, Daniel Varghese, “Aesop's Hand Sanitizer Is a Flex for an Anxious Time”, in GQ:

verb

1. (transitive, chiefly physics or biomechanics) To bend something.
2. (transitive) To repeatedly bend one of one's joints.
3. (transitive) To move part of the body using one's muscles.
4. (intransitive) To tighten the muscles for display of size or strength.
   He rubbed his hands together. "Believe it or not, there was a time when I considered giving acting a go. What do you think, Miss Fox?" He flexed impressive biceps. "Would I have had a chance against the Schwarzeneggers and the Chuck Norris types?" 1994, Elise Title, Body Heat, page 189
5. (intransitive, slang, by extension) To flaunt one's superiority.
   I've got billions and billions of rhymes to flex / 'Cause I've got more rhymes than Carl Sagan's got turtlenecks 2004, “Hey Fuck You”, in To the 5 Boroughs, performed by Beastie Boys
   They say it's lonely at the top, but this the best shit ever / Hey, don't you see me out here shinin'? Bitch I'm barely flexin' 2017, “Kill Jill”, in Boomiverse, performed by Big Boi ft. Killer Mike & Jeezy