The art of using VERY long words to confuse people. It comes from the root 'sesquipedalian', which means one who uses long words to (again) confuse people. Source: Mrs. Burns Dictionary of Obscure, and Preposterous Words.
Hippopotomonstrosesquipedalianism is the art of utilizing extremely elongated lexicons to give the appearance of being more intelligent to one's acquaintances.
Fear of long words. Since 'sesquipedaliaphobia' already means fear of long words, the other part is added on by those with hypopseudoliteratiobfuscationarianism.
"Homer retaliated, triggering Aesop's hippopotomonstrosesquipedaliaphobia with a hypopseudoliteratiobfuscationarionisticism of his own before jumping to a floccinaucinihilipilification of the whole process."