Chillul haShem (Hebrew: חילול השם "desecration of the Name"), meaning desecration of the name of God, is a term used in Judaism for any act or behavior that casts shame or brings disrepute to belief in God, any aspect of the Torah's teachings, Jewish law, or the Jewish community.
The source for this commandment is found in the Leviticus 22:32: "And you shall not profane My holy name; but I will be hallowed among the children of Israel: I am the Lord who hallows you".
Any behavior or action that disgraces, harms or shames God and his Law is regarded as desecration of God's name, Chillul Hashem. Every sin a Jew does is Chillul Hashem.
The opposite concept, kiddush Hashem (sanctification of Hashem), means any action that brings honor, respect, and glory to God. It is often used to mean religious martyrdom. The obligation to refrain from desecration of Hashem is one of the 613 commandments in rabbinical enumeration.