Slang term for a complicated and/or uncommon word. Usually derogatory, referring to a word used in place of a simpler alternative for the purpose of showing off the speaker or writer's vocabulary, rather than to improve the clarity of the message.

"I never write metropolis for seven cents because I can get the same price for city. I never write policeman because I can get the same money for cop."
-Mark Twain

When the machines are high-priced or when only a mathematician can understand them, we use the two-dollar word "automation"; when the machine is an average-priced one that high-school students can understand, the one-dollar word "mechanization" is used; for low-priced machines anyone can operate, we use the fifty-cent word "labor-saving".
-Donald A. and Eleanor C. Laird in "How To Get Along With Automation"