The Jewish Underground was a Jewish terrorist organization formed by prominent members of the Israeli political movement Gush Emunim that existed from 1979 to 1984. The group's highest profile plot was to destroy the Dome of the Rock in Jerusalem. According to page 48 of this book, the founding clique contained four members: Yehuda Etzion, Menachem Livni, Yeshua Ben-Shushan and Dan Be'eri.
The name was also used by the Israeli media for several other Jewish groups, including the Kahanist group, Terror Neged Terror.
The convicted members of the Jewish Underground were: Menachem Livni, Moshe Zar, Hagai Segal, Yehuda Etzion, Yeshua Ben-Shoshan, Ze'ev Hever (Zambish), Dan Be'eri, Uzziah Sharaf, Nathan Natanson, Chaim Ben-David, Yitzhak Geniram (Akala), Barak Nir, Shaul Nir, Ben-Zion Henman, Jacob Henman, Boaz Hanman, Yitzhak Novick, Gilad Peli, Yossi Zuria, Menachem Neuberger, Avinoam Katrieli, Uri Meir, Ira Rapaport, Noam Yinon, Yehuda Cohen
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See this Wikipedia (Hebrew) article (English translation)