Fustian is overblown, pretentious speech or writing. If you're a careful reader, a novelist's fustian won't disguise his book's flimsy plot and stereotypical characters.
Announcing your arrival at school by saying, "It is I, the very heart and soul of this school — colleagues, let education commence!" is an example of fustian. The chess club captain might start each practice with fustian, pompously reflecting on the history of the game, the intellect of a great player, and his own importance as leader of the team. This term, which originally meant "rough twill cloth," was used in its "pompous talk or bombast" sense by Shakespeare in Othello.