Bestie being best friend, obviously.
Mate being crush or lover, your choice.
Idol meaning you look up to them or admire them.
Rival meaning you don't really hate them but you can't stand them either.
Well, yes, it can mean that too. I just specified because I didn't people to think I meant mating as in reproduction which I didn't. I'm gonna be posting characters and people will have to decide which one they want to place them as.