Self Defense Tips Needed

I'm currently in a situation which, without describing the nitty gritty details, means that I have to frequently be in close proximity to a very unhinged and violent person (think: sociopath type psycho) who has threatened to physically assault me (specifically to stab me). I've overheard this person share many stories about how they have beaten people up.

There is nothing I can do about the fact that I must see this person repeatedly, and going to the police would only put me in more danger, as the person could then learn my real name and address. Also, the police in my city notoriously don't respond to or pursue low-level crimes like threats.

What self defense tips do you have? I couldn't find any specific self defense subs so hopefully some people on here will have some ideas or experience in needing self defense.

So far I am thinking of carrying pepper spray on me but besides that I have no idea.