Surah Ad-Dukhan 44:14

ثُمَّ تَوَلَّوْا۟ عَنْهُ وَقَالُوا۟ مُعَلَّمٌ مَّجْنُونٌ

Then they turned away from him and said, "[He was] taught [and is] a madman."

Translation: Saheeh International

Tafsir

but they turned away from him and said ‘He has been taught — that is a human being is teaching him the Qur’ān — he is a madman!’

Excerpt from Tafsir al-Jalalayn, commentary on 44:14, via Quran.com. The reader has the full commentary and 9 more tafsirs.