For he was a poet and drowned untimely, and his verse, mild as it is and formal and sententious, sends forth still a frail fluty sound like that of a piano organ played in some back street resignedly by an old Italian organ-grinder in a corduroy jacket.
-- Virginia Woolf, "Street Haunting: A London Adventure," Collected Essays
It was inconceivable that she was using the boring, sententious, contentious Shepherd for anything but a hollow threat to him, but this semblance of wrongdoing could now be turned to advantage.
-- Kurt Vonnegut, Player Piano
Sententious is related to sententia, the Latin root for the word sentence. The Latin word sententiosus meant "full of meaning, pithy."