When someone uses a needlessly complicated or esoteric word when a simpler word or expression would suffice.
A common occurence amongst neophyte academics who wish to impress peers.
A word used to purposefully end or redirect a conversation or train of thought. It is usually deployed in uncomfortable situations against someone who is known to have a more limited vocabulary.
Joey dropped a vocabularity on his high school drop out mom. He made her think his sister was having a crisis of sexuality by telling her she wanted to be a thespian.