flimsy

Etymology

Uncertain. First used in the 18th century. Perhaps a metathesis of film + -s + -y; or related to flimflam.

adj

1. Likely to bend or break under pressure.
   He expected the flimsy structure to collapse at any moment.
   All the flimsy furniture of a country miss's brain. 1715, Richard Brinsley Sheridan, The Rivals
2. (figurative) Weak; ill-founded.
   a flimsy excuse

noun

1. Thin typing paper used to make multiple copies.
   Smiley peered once more at the flimsy which he still clutched in his pudgy hand. 1977, John Le Carré, The Honourable Schoolboy, Folio Society, published 2010, page 251
2. (naval slang) A service certificate
   A perusal of the comments of officers under whom he has served as recorded in his “flimsies" indicates that he has almost consistently received high commendation for his service. 1964, Australia. Parliament, Records of the Proceedings and Printed Papers of the Parliament
   Regulations required a commanding officer to render annual confidential reports on the character and ability of his officers - with particular reference to sobriety - on forms known as 'flimsies'. 1994, John Wells, The Royal Navy: An Illustrated Social History, 1870-1982, page 7
3. (informal, in the plural) Skimpy underwear.
   Choosing lingerie “is about what makes you look good, but also what looks good with or through your clothing,” said Monica Mitro, a spokeswoman for Victoria’s Secret, the brand that catapulted racy flimsies into the public eye. October 25, 2007, Ruth La Ferla, “Now It’s Nobody’s Secret”, in New York Times
4. (slang) A banknote.