magniloquence (n.)

"exaggerated eloquence, loftiness of speech or expression," 1620s, from Latin magniloquentia "elevated language, lofty style," from magniloquus "pompous in talk, vaunting, boastful," from combining form of magnus "great" (from PIE root *meg- "great") + -loquus "speaking," from loqui "to speak" (from PIE root *tolkw- "to speak").