Good Samaritan: Someone who voluntarily helps someone else who is in distress.
The term "Good Samaritan" comes from the parable of the Good Samaritan related in the Book of Luke in the New Testament of the Bible. The parable tells of a Samaritan (a resident of Samaria) who stopped to help a man who had been injured and robbed, while others passed him by.
A number of hospitals and medical centers bear the name "Good Samaritan." See also Good Samaritan law.