sesquipedalian

(noun) a very long word (a foot and a half long). Synonyms: sesquipedalia.

(adj) given to the overuse of long words. Examples: "Sesquipedalian orators." "This sesquipedalian way of saying one has no money."

(adj) (of words) long and ponderous; having many syllables. Synonyms: polysyllabic. Example: "Sesquipedalian technical terms."