نيابة عن بالانجليزي

on behalf of somebody | on somebody’s behalf: as the representative of somebody or instead of them

وَقَّعَ وَزِيْرُ الخَارِجِيَّةِ الإِمَارَاتِيُّ اتِّفَاقَ السَّلَامِ مَعَ إِسْرَائِيْلَ نِيَابَةً عَنْ رَئِيْسِ الإِمَارَاتِ

The Minister of Foreign Affairs of the United Arab Emirates signed the peace agreement with Israel on behalf of the president

حَضَرْتُ نِيَابَةً عَنْ وَالِدِي

I've come on my father behalf

in order to help somebody

كَافَحُوْا نِيَابَةً عَنِ المَدَنِيِّيْنَ المَقْهُوْرِيْنَ

They fought on behalf of the oppressed civilians