It means a person with special graces from God. The Reformers were not,like so many present day evangelicals ones who thought that he had been chosen by God was among the Elect. Saints are God’s chosen few, often times unknown but to him; while others, who may seem that way to the world, are not.
Saints are God’s chosen few...
Interestingly, that is how I see those who have been chosen by God. That is, all of what the Bible calls “the saints”. The believers.