Noun

1. An often-quoted saying that is supposed to be meaningful but has become unoriginal or hackneyed through overuse; a cliché.
   • 1918 — Algernon Blackwood, The Garden of Survival, ch XI

     Beauty, I suppose, opens the heart, extends the consciousness. It is a platitude, of course.

2. Unoriginality; triteness.
3. A claim that is trivially true, to the point of being uninteresting.