All 4 Uses of

platitude
in
This Side of Paradise

Once he dreamt that it had come true and woke up in a cold panic, for in his dream she had been a silly, flaxen Clara, with the gold gone out of her hair and platitudes falling insipidly from her changeling tongue.†
Chpt 1.4

platitudes = things so commonly repeated that they are no longer interesting

Here is what he had written: "Songs in the time of order You left for us to sing, Proofs with excluded middles, Answers to life in rhyme, Keys of the prison warder And ancient bells to ring, Time was the end of riddles, We were the end of time... Here were domestic oceans And a sky that we might reach, Guns and a guarded border, Gantlets—but not to fling, Thousands of old emotions And a platitude for each, Songs in the time of order— And tongues, that we might sing."†
Chpt 1.4

There is no more dangerous gift to posterity than a few cleverly turned platitudes.†
Chpt 1.4 *

platitudes = things so commonly repeated that they are no longer interesting

If he can be educated to think clearly, concisely, and logically, freed of his habit of taking refuge in platitudes and prejudices and sentimentalisms, then I'm a militant Socialist.†
Chpt 2.5

Definition:

something so commonly repeated that it is no longer interesting