That's funny, because of the two terms, "junk bond" seems to me to be the more accurate and descriptive one, while "high-yield bond" seems like a deliberately deceptive euphemism.
when major banks/investors refused to deal with BBB or lower they called it 'Junk'. When they realized 1) the credit risk can be safely managed with modern financial theory and instruments 2) there was money to be made ... they quickly adopted it and had to figure something out to drop the 'Junk' pejorative.