Tzaddik צדיק is a form of the Hebrew verb צדק [TzDK], which carries the meaning of doing what is correct and just.
The personality of the tzaddik is calibrated to the Manufacturer’s original specifications, so that everything about him is just as his Creator meant it should be, and all he desires is what his Creator desires. A tzaddik is one who embodies the Creator’s primal conception of the human being.
The tzaddik is a human being like all of us. Because, essentially, all of us are divine.
Which means that the tzaddik is a human being like all of us. The tzaddik feels pain and pleasure. He grins, he smiles, he cries and he laughs. He suffers bitterness of the spirit, and he dances with joy. At times his heart palpitates with love, and at others his veins burn with outrage. He is frustrated by failure, exhilarated by success; he revels in the celebrations of life, and mourns when those he loves depart from it. Because all these things are included in the character of the human being as G‑d made him, and so they too are divine.