Rahab was, according to the Book of Joshua, a woman who lived in Jericho in the Promised Land and assisted the Israelites in capturing the city by hiding two men who had been sent to scout the city prior to their attack. In the New Testament, she is lauded both as an example of a saint who lived by faith, and as someone "considered righteous" for her works.
The King James Version renders the name as Rachab, after its literal spelling in Greek, which differs from the spelling for Rahab in James and Hebrews. Most modern versions render it as Rahab ignoring the distinction.