G-d – When the name of God is written in Hebrew, it can never be destroyed – and there are several names for Him in Hebrew. As a way around this, we often will write the name with alternate letters in Hebrew so as to not create a problem. Similarly, most orthodox jews will write G-d in English with the hyphen.
Gabbai- the guy in the shul responsible for arranging who leads the prayers and gets called up to the Torah, etc.
Galus- exile, diaspora
Gam Tzu La Tova- "This also is for the good." A classic phrase used to show faith that everything that happens is from G-d and therefore inherently Good.
Gan Eden – Literally the Garden of Eden, this can refer to the “heaven”/afterlife
Gebentched - one who is blessed
Gehinnom – Purgatory or Hell depending on who you ask
Gemara - part of the Talmud, the code of Jewish Law
Gematria - the Jewish system of numerology, based on the numeric value of Hebrew letters
Ger – a convert
Get - divorce decree that ends a Jewish marriage
Godol HaDor, Nosi HaDor – the leader of the generation
Grusha - Hebrew, means divorcee
Gutte gebentched yohr – Yiddish, means a Good, Blessed Year – this is a new year’s greeting
Gutte voche – Yiddish, means a good week, something said after the shabbos/Sabbath ends