threadbare phrase

"I've always done my duty by him," she continued, returning to the threadbare phrase that was ever present in her mind.

You know that threadbare phrase, noblesse oblige?

"Hurry up!" was about the most threadbare phrase in the English language, and rather than "E pluribus unum" should especially have been the motto of the American people, but it was the first time the note of haste had impressed my consciousness since I had been living twentieth-century days.