He who prevents to happen what He does not want to happen. He who prevents the harm.
“They said: “O Moses! while they remain there, never shall we be able to enter, to the end of time. Go thou, and thy Lord, and fight ye two, while we sit here (and watch).” He said: “O my Lord! I have power only over myself and my brother: so separate us from this rebellious people!” Allah said: “THEREFORE WILL THE LAND BE OUT OF THEIR REACH FOR FORTY YEARS: IN DISTRACTION WILL THEY WANDER
THROUGH THE LAND: but sorrow thou not over these rebellious people.”
(5:24…26) The Holy Quran
From the root m-n-' with the classical Arabic connotations: to prevent, hinder, hold back, restrain, deny to impede, resist to forbid, refuse, prohibit to guard, defend, protect.