Okay I've thought about this for a while now. There's no exact german word for this. Closest thing I could think of is "spinnefeind" (direct translation is spider enemy). If you say someone is spinnefeind to you, you despise this person and everything he does/says, without any apparent reason.
Can confirm?
It sounds like a word my best friend would make up to be honest xD
But there needs to be a word