Gerology

In Rabbinic times (from the 1st century CE to the closure of the Babylonian Talmud, c. 600 CE) the definition of a ger varied. 

Thus, there was the Ger Tzedek, the “just” or full ger, who willingly lived as a Jew in all respects and observed all the commandments.

The Ger Toshav, the “resident alien,” who lived among Jews and, though not fully observant, renounced idolatry and other pagan practices.

The Ger Arayot, the “lion ger,” who accepted Judaism out of superstition rather than informed conviction (based on the story in Kings II about how the Samaritans, the people brought to Samaria after the exile of its Israelite inhabitants by the Assyrians, began to worship the Israelite G-d, because they thought He was the reason for the lion attacks).

The Ger Ester u’Mordekhai, the “Esther-and-Mordecai ger,” who converted in fear of Jewish violence or persecution (based on the last chapter in the book of Esther).

The Ger To’eh,  “mistaken ger,” who practiced Judaism on his own and incorrectly.

The Ter Garur, the “[self]-attached ger,” someone who considered himself a Jew because he associated with Jews, even though they themselves did not think of him as such.