Well if you dont want to be rude by unfriending them you could always try and tell them how things are and you just dont want to talk with them right now or well if its more like you really dont want to talk with them then its like no use to even be friends, i know its rude but that will kinda be the way out of it. Know alot with people that just text you when you dont want to like talk to them and sometimes i just look like i'm AFK by not responding to those who i dont want to talk with, and if they dont stop i ask them to either stop and stuff like that