Okay kiddo, let me explain what a "refusenik" means.
You know when you and your friends play a game and sometimes you don't want to play anymore or you don't want to do what your friends are doing? That's similar to what a refusenik is.
A refusenik is someone who refuses to do something that everyone else is doing.
But there's a specific kind of refusenik. This word is usually used to describe Jewish people who refused to leave Russia during a time when the government didn't want them to leave.
The government was trying to control where people lived and worked, and they wanted Jewish people to stay in Russia even if they didn't want to. But some of the Jewish people didn't want to stay and decided to leave anyway, even though it was against the law. These people were called refuseniks because they were refusing to follow the government's rules.
So, a refusenik is someone who refuses to do something that everyone else is doing or what the law says they should do.