“Official” Definition:
“...any expression so often used that its freshness and clarity have worn off…probably begins as an arrestingly colorful expression, possibly in a literary work, but heedless repetition soon dulls the original brightness.”
Harmon, William, et al. A Handbook to Literature. 8th ed., Upper Saddle River, Prentice Hall, 2000.
Informal Definition:
A cliche is a phrase or, in some cases, an idea that is used extensively, to the point that the meaning is lost and is no longer interesting.
Ex: “Better Late than Never”; “Dead as a doornail”
Origin/Etymology:
“1825, "electrotype, stereotype," from French cliché, a technical word in printer's jargon for "stereotype block," noun use of past participle of clicher "to click" (18c.), supposedly echoic of the sound of a mold striking metal (compare native click)...extension to "trite phrase, worn-out expression" is first attested 1888, via the notion of the metal plate from which a print or design could be reproduced endlessly without variety, paralleling the sense evolution of stereotype.”
Harper, Douglas. "cliche (n.)." Online Etymology Dictionary, 8 Aug. 2008, www.etymonline.com/search?q=cliche&ref=searchbar_searchhint. Accessed 29 Aug. 2022.