childishly foolish; immature or trivial.
vulgar or indecent in speech, language, etc.; coarsely mocking, abusive, or irreverent; scurrilous.
lacking in vitality, imagination, distinction, etc.; commonplace; prosaic or dull.
indecent; somewhat obscene; risqué.
My experience is that these words generally work best when you say them with your nose in the air. Try it: "I found that author's writing to be rather pedestrian." Add a sniff after the close for added impact.