What is 'urf (custom), to what extent is it taken into account in religious matters, and what is its rank?

Custom ('Urf) is what people are accustomed to and what they follow from every action widespread among them, or a word they have agreed upon to use for a specific meaning. It is taken into consideration in religious matters if it is sound and does not contradict Islamic law. As for corrupt custom, it is that which permits what is forbidden or forbids what is permissible. The jurists have agreed that custom is an evidence or a source among the sources of Islamic legislation. Custom is considered (valid) if four conditions are met: that it is consistent or prevalent, that it exists at the time of the creation of the act, that it does not contradict an explicit statement to the contrary, and that it does not violate a religious text or a definitive principle. Textual evidence and consensus take precedence over custom, while custom takes precedence over analogical deduction (Qiyas (definition)) if they conflict.