The Hebrew term zavah (Hebrew זבה) is a state of ritual impurity applicable to females arising from vaginal blood discharges not during the usually anticipated menstrual cycle.
In the realm of tumah and taharah, the zavah has the ability to create a midras, (Leviticus 15:4, Leviticus 15:9,Leviticus 15:26 and to make unclean for a seven-day period - a man who conducts sexual intercourse with her. Additionally, the zavah woman and her partner are liable to kareth for willfully engaging in forbidden sexual intercourse.
Torah sources for the zavah are sourced in the book of Leviticus(Leviticus 15:1-15, Leviticus 15:25-33) According to textual scholars, the regulations concerning childbirth,(Leviticus 12) which have a similar seven-day waiting period before washing, and the sin and whole offerings, were originally suffixed to those concerning menstruation, but were later moved.
Further specification of these rules exist in the Oral Law; Orthodox Judaism views the Shulchan Aruch as being particularly authoritative on these matters, and it has extensive discussion about the subject.
The zavah state is described as initiating itself post the cessation of the usual blood flow of the menstrual cycle. The woman is described as having already immersed in a mikveh and currently in a tahor (pure) state.