The biblical term "proselyte" is an anglicization of the Koine Greek term προσήλυτος (proselytos), as used in the Septuagint (Greek Old Testament) for "stranger", i.e. a "newcomer to Israel"; a "sojourner in the land", and in the Greek New Testament for a first century convert to Judaism, generally from Ancient Greek religion. It is a translation of the Biblical Hebrew phrase גר תושב (ger toshav).
"Proselyte" also has the more general meaning in English of a new convert to any particular religion or doctrine.
The Law of Moses made specific regulations regarding the admission into Israel's community of such as were not born Israelites.
The New Testament makes mention of proselytes in synagogues. The name proselyte occurs in the New Testament only in Matthew and Acts. The name by which they are commonly designated is that of "devout men", or men "fearing God", or "worshipping God", or "Godfearers".
On the historical meaning of the Greek word, in chapter 2 of the apocryphal gospel Acts of Pilate (roughly dated from 150 to 400 CE), Annas and Caiaphas define "proselyte" for Pilate:
And Pilate, summoning the Jews, says to them: You know that my wife is a worshipper of God, and prefers to adhere to the Jewish religion along with you. ... Annas and Caiaphas say to Pilate: All the multitude of us cry out that he [Jesus] was born of fornication, and are not believed; these [who disagree] are proselytes, and his disciples. And Pilate, calling Annas and Caiaphas, says to them: What are proselytes? They say to him: They are by birth children of the Greeks, and have now become Jews.