In Islamic law, najis (Arabic: نجس‎) means ritually unclean. According to Islam, there are two kinds of najis: the essential najis which cannot be cleaned and the unessential najis which become najis while in contact with another najis. Contact with najis things brings a Muslim into a state of ritual impurity (Arabic: نجاسة‎ najāsa, in opposition to ṭahārah, ritual purity). Ritual purification is then required before religious duties such as regular prayers are performed.