There are at least two people in the Bible named Zimri. One was a king. The other was a son of Salu, a Simeonite prince, in Numbers 25:14.
Zimri, the son of Salu, brought a Midianite woman named Cozbi into camp while Israel was repenting for having worshiped Baal. When Phinehas, the son of Eleazar, saw Zimri take her to his tent, he was enraged, took a javelin in his hand, went into Zimri's tent, and thrust both of them through.
The other Zimri - the king - was the fifth king of the northern kingdom of Israel. He killed Elah, son of Baasha, and declared himself king. He tried to protect his hold on the throne by killing the male heirs of Elah.
This fulfilled a prophecy of Jehu about the destruction of the family of Baasha (1 Kings 16:3). King Zimri reigned for only seven days. When members of the army had learned of what had Zimri had done, they appointed Omri as their commander. After a successful attack by Omri and the army, Zimri went into the palace and set fire to it. He died in the flames.
The name Zimri is featured in 2 Kings 9:31 as an example of someone who has killed his master.
The story of King Zimri is found in 1 kings 16:8-20.
Next person in the Bible: Zipporah