dont outright tell them you don't want to be friends with them anymore because that'll be really awkward. my answer will depend on if this is an online or irl friend soo...
online: ik it may be hard or embarrassing but just blockthem. if you have lots of mutual friends or even just one mutual friend and you don't want drama to spark up don't blockbut stop replying or even checking to see what they said because that'll make you want to reply.
irl: do NOT unfriend them to their face, just avoid them, stop saying hi to them or acknowledging them. eventually this will drain them out of interest of you and will drift apart. be really dry and passive aggressive, but not blunt aggressive, because then they'd have a reason to call you out. passiveness will make it obvious you don't wanna talk to them and they cant talk on it. if they DO end up asking you why you're being so distant or mean just act like you don't know what they're talking about or a half-assed apology. (only be passive aggressive if they don't already get the hint on you ignoring them) and try to hang around with other friends a lot, because if they see you alone they have an easier advantage to talking to you. ok idk what else BYE
I disagree with the other person, don't be passive aggressive or whatever. Literally such a waste of time, just to blunt and straightforward to save yourself allat effort. Tell them straight to their face that you don't fw them or their disgusting tastes and to leave you alone, then blockthem.
If they try to annoy you or cause drama, literally expose them. So collect evidence beforehand and store them nice and safe.
I mean, exposing them is a last ditch effort AFTER drama has been initiated by the other party. That's why collecting all evidence matters and you'll need to play your cards right. Best case scenario, they just leave you alone after you've broken off f2f or blocked them, either way in my experience, being passive aggressive is just gonna lead to more problems bc then the other person will get offended and try to confront OP sooner or later. Ts is complicated and honestly completely depends on the situation

how do i cut off a friend who likes shotas, and keeps harassing me to find a shota and lolis website and shits