An idea or expression that has lost its originality or its force, and become trite because of its overuse. A stereotype. Most clich?s become popular over the years because they express a thought aptly and concisely, when, if used too often, their aptness can be overwhelmed by their dullness.(pr. klee-SHAY)Quotes: "The difference between the right word and the almost right word is the difference between lightning and the lightning bug." Samuel Clemens, aka "Mark Twain" (1835-1910), American writer. "Avoid clich?s like the plague. (They're old hat.)" Anonymous.