I'm looking for a noun for a person you don't like, but does not reveal any more information about that person besides disliking them/
You could use "enemy", "antagonist", "adversary", "foe", "rival", or "opposition".
I would suggest:
Someone who you dislike. Longman Dictionary
A person who you do not like. Longman Dictionary
But I prefer creep:
"Leave me alone you creep." Merriam Webster
"He was a real creep, he was always staring at me in the canteen." Cambridge advanced Learner's
You could use an adjective + the word person, as in:
"An unpleasant person"
"A disagreeable person"
As an alternative, you could use the latin term persona non grata (literally "disagreeable person").
Bête noire: A detested person (WordWeb on line) - from French, but an English loan word.
anathema (same definition, same source)
A bit harsh, but can be used humorously
thorn in my side
Possibly the best option.
I've always thought degenerate was a great word and nobody ever uses. I.e. A real low life.
Or reprobate. Scoundrels good too. They all mean the same pretty much. For some reason my mind always goes straight to old timey.
"He's a bad egg that one. A good-for-nothing miscreant! One day that scurrilous naer-do-well in going to wind up in real hot soup. This ain't no line of bushwa I'm feeding you either."
Great habit too in real life. When the situation gets serious you really want a word like "Rapscallion" to be the the first thing out of your mouth.
I'll go with putoff.
put someone off (also put off someone): to cause someone to dislike someone Cambridge Dictionary of American Idioms
That dude is a putoff. For some reason I can't explain, I just can't stand/bear the sight of him.
M-W recognizes use of the word antipathy for:
3 : an object of aversion
Although phrases like he is my antipathy" seem to be very rare in English and probably a calque.