The noun cliché means an idea or phrase that is often made and no longer effective or no longer has much meaning.
Synonyms are motto, overused, commonplace, or old story.
The word origins from French (18th century) cliché, a technical word in printer’s jargon for “stereotype block”, noun use of past participle of clicher meaning “to click” supposedly echoic of the sound of a mold striking metal.
I know it’s a cliché, but I think I can’t live without you.
I don’t dispute that cliché. In fact, I can relate to it well.
It may sound cliché but it’s true.