The worst word in audio is "best," as in "What is the best DAC on the market today?" or "What is the best speaker for under $8k?" or more relevant to your question, "This amplifier [the one for sale] is the best amp I've ever heard."
What are the current useless terms in this "audio world"
Throughout the history of marketing of all kinds of consumer goods there have been many useless, hyperbole phrases and words used. It seems on ebay, here, craigslist and others a current pet of Sellers is taking something to "the next level".... which sounds like a great marketing term for an elevator maker.