repeated too often; overfamiliar through overuse; "bromidic sermons"; "his remarks were trite and commonplace"; "hackneyed phrases"; "a stock answer"; "repeating threadbare jokes"; "parroting some timeworn axiom"; "the trite metaphor `hard as nails'"
Threadbare clothes, carpets, and other pieces of cloth look old, dull, and very thin, because they have been worn or used too much. She sat cross-legged on a square of threadbare carpet. = worn
If you describe an activity, an idea, or an argument as threadbare, you mean that it is very weak, or inadequate, or old and no longer interesting. the government's threadbare domestic policies