proselyte

[Anthony]

A righteous proselyte[5] was a Gentile who had converted to Judaism, was bound to all the doctrines and precepts of the Jewish economy, and was considered a full member of the Jewish people. They were to be circumcised and immersed in a mikvah should they wish to eat of the Passover sacrifice. A gate proselyte[6] was a "resident alien" who lived in the Land of Israel and followed some of the customs. They were not required to be circumcised nor to comply with the whole of the Torah. They were bound only to conform to the seven precepts of Noah, the Noahide Laws: do not worship idols, do not blaspheme God's name, do not murder, do not commit immoral sexual acts, do not steal, do not tear the limb from a living animal, and do not fail to establish courts of justice.

Used in this verse:

Matthew 23:15
“Woe to you, scribes and Pharisees, hypocrites! For you travel land and sea to win one proselyte, and when he is won, you make him twice as much a son of hell as yourselves.

http://en.wikipedia.org/wiki/Proselyte
http://www.biblegateway.com/passage/?sea...rsion=NKJV