Webster’s Dictionary defines tzaddik as “a righteous and saintly person by Jewish religious standards.”
“Often people call someone a tzaddik simply because he is an exceptionally good person. Then there are times they come across a spiritual superhero, someone more like an angel than a human being, and they say, “Now that’s a tzaddik!” Yet the most special thing about a tzaddik is that he really is the most human of human beings.
The tzaddik is a human being like all of us. Because, essentially, all of us are divine.”
— Tzvi Freeman, chabad.org