Ger Tzedek (Hebrew: גר צדק, ger tzedek -- "righteous proselyte" or "proselyte [of] righteousness"), is a term used in Judaism to refer to a gentile who convert to Judaism. It may be abbreviated as simply ger (Hebrew: גר, ger -- "stranger" or "proselyte").
According to Kellner (1991) on Maimonides, a ger toshav (or Noahide) could be a transitional stage on the way to becoming a ger tzedek. He conjectures that only a full ger tzedek would be found at the time of the Messiah.
The conversion involves circumcision for men and a bath called Mikveh in the presence of three judges (Daian). For women only the Mikveh bath in the presence of three judges is required. Ger Tzedek are considered born-again children of Abraham and Sarah who have placed themselves under the Shechinah.