Tzadik/Zadik/Sadiq (Hebrew: צדיק‎ "righteous one", pl. Tzadikim צדיקים ṣadiqim) is a title given to personalities in Jewish tradition considered righteous, such as Biblical figures and later spiritual masters. The root of the word ṣadiq, is ṣ-d-q (צדק Tzedek), which means "justice" or "righteousness", also the root of Tzedakah (Charity, lit. "righteousness"). The feminine term for a righteous person is Tzadeikas.

Excerpt copied with permission from the relevant Wikipedia article.