RadhiAllahu’anhu (Arabic: رضي الله عنه raḍiya ‘llāhu ʿan-hu) is an Arabic honorific phrase meaning, “May Allah be pleased with him.” It is a phrase commonly after the name of one of Prophet Muhammad’s (ﷺ) Companion’s is mentioned. Grammatical variations exist for situations when female companions are mentioned (RadhiAllahu ‘anha رضي الله عنها) or in plural references of the Sahaba (RadhiAllahu ‘anh’um رضي الله عنهم).
Examples in The Quran
“Indeed, Allah was pleased with the believers when they pledged allegiance to you ˹O Prophet˺ under the tree. He knew what was in their hearts, so He sent down serenity upon them and rewarded them with a victory at hand,” 
﴾ لَّقَدْ رَضِيَ اللَّهُ عَنِ الْمُؤْمِنِينَ إِذْ يُبَايِعُونَكَ تَحْتَ الشَّجَرَةِ فَعَلِمَ مَا فِي قُلُوبِهِمْ فَأَنزَلَ السَّكِينَةَ عَلَيْهِمْ وَأَثَابَهُمْ فَتْحًا قَرِيبًا ﴿
- Jump up↑ Qur’an [48:18] Al-Fath (The Victory, Triumph) – سورة الفتح