The ʿurfī (customary) meaning applies when a figurative sense has become so widespread that it overrides the literal sense¹—such as rāwiyah, which originally meant a water-skin but now denotes a heavy drinker, or ghā’iṭ, which literally referred to a low-lying spot but is now used for excrement. In these cases an oath is governed by common usage: if a man swears not to “approach” his wife or to “approach” a house, his oath attaches to having intercourse with her and to entering the house.

If someone swears not to eat a particular thing, and then consumes it only after it has been completely absorbed into something else—like a man who swears not to eat clarified butter but eats khabīs (a sweet paste) in which the butter is present yet its taste is imperceptible, or who swears not to eat eggs but eats nāṭif (a cream dessert)—he is not perjured. However, if the taste of any item he has sworn off is detectable, he is perjured².

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If a person swears that he will not do something—such as speaking to Zayd or entering Zayd’s house—and then does it under compulsion, he is not perjured.

If he swears concerning himself—or concerning someone he intends to restrain, like his wife or child—that a certain act will not be done, and it is done out of forgetfulness or ignorance, the oath is deemed broken only in the case of oaths that effect divorce or manumission. But if the one he seeks to restrain would not be deterred by the oath, such as a ruler, and that person proceeds to do the act, the swearer is perjured without qualification. Likewise, if either the swearer or the person he aimed to restrain performs only part of what he had sworn absolutely not to do, he is not perjured—unless he specifically intended to include partial performance.