Shamoom (شمعون) is an Hebrew (عبرانی) name, and unfortunately the meaning is unknown.
According to Bible, Yaqoob (یعقوب) A.S aur Leah (لیاہ) kay doosray betay ka name Shamoon hai, yeh Hazrat Yousuf (یوسف) A.S kay soutelay bhai hein, aur Bani Israel k 12 qabail may say qabeelah Shamoon in k name say mansoob hai. Hazrat Yousuf ki walidah ka name Raheel (راحیل) tha, aur yeh Hazrat Yaqoob A.S ki doosri zojah theen.
I will update more detail on the name page: Shamoon