Definition: noun 1a: a word or saying used by adherents of a party, sect, or belief and usually regarded by others as empty of real meaning b: a widely held belief c: truism, platitude   2a: a use of language regarded as distinctive of a particular group b: a custom or usage regarded as distinguishing one group from others.

Etymology: Hebrew shibbōleth stream; from the use of this word in Judg 12:6 as a test to distinguish Gileadites from Ephraimites

Quotation: “Now we are 12 years into the reign of Tiger Woods. At 32, he is just entering the period traditionally considered a golfer’s prime, no longer the man-child who overthrew all those sports shibboleths about waiting your turn and the value of experience but a paradigmatic champion, with gray at his temples and his hair in retreat.”
- from “It’s Good to Be Immortal” in The New York Times “Play” Magazine

While “truism” and “platitude” are both serviceable smart words, “shibboleth” is a cut above. It might be a bit too exotic for conversational or spoken use (I doubt you’ll hear one of the presidential candidates talking about the trite shibboleths uttered by their opponent), but it fits nicely into a written piece.
Let me just add here that The New York Times “Play” Magazine is the best serial sports publication out there. Unlike the regular magazine which comes out every Sunday you have to wait a whole month for Play, but it’s worth it. If you’ve never had the pleasure of flipping through the pages, try the e-edition here.