Junub - a person having Janaba - means to be in a state of ceremonial impurity or defilement. A male becomes junub on having sexual intercourse or simply on the emission of semen in sleep or otherwise. A female also becomes junub as a result of sexual intercourse as well as when she is menstruating or having postnatal bleeding. These are the general causes of janaba, which is also referred to in the books of jurisprudence as hadath akbar. A full bath is required for a junub to receive purification or tahara, without which a man or woman is not allowed to touch or read the Qur'an, enter the mosque or offer the prayers. In the absence of water, however, one is allowed to resort to tayammum. Tayammum substitutes for both a full bath (ghusl) and ablution (wudu).