What's another educated word for "Hater", as in someone who wants to see another fail or lose and uses negativity to do so?

Ex. This type of person will say or do something negative to you when you accomplish something great in life, simply because they want to put you down and hurt your self esteem or confidence. No one asked their opinion, they simply lash out negative verbal attacks or actions to put you down.

For lack of better words, I would say, "You're just a hater".

However, the word "hater" by its definition would not make sense in this statement. Let's say you could prove in court and to anyone that this person does not hate you at all. So if they're not a "hater" of you, what word would describe them?

Solution 1:

One word that may work for you is adversary. It has a considerably higher register than hater.

one that contends with, opposes, or resists: an enemy or opponent — MW

Also consider the adjective adversarial or perhaps a synonym of it such as hostile.

Solution 2:

Detractor would come close.

Lexico

detractor

NOUN

A person who disparages someone or something.

There is no excuse, however, for a man in this enlightened age, who professes to be a spiritual leader of the people, to remain ignorant of an important fact, or to continue to see that fact through a false medium, when he has the opportunity of coming into Wall street and seeing for himself. He has no right to set himself up as a censor, a public detractor, and a public libeller upon a set of men and merchants who are the bone and sinew of the financial, commercial, and industrial interests and prosperity of the country. (Delusions about Wall Street, Henry Clews, North American Review: Ocotber 1887: 410-422)