Surah Taha 20:121

فَأَكَلَا مِنْهَا فَبَدَتْ لَهُمَا سَوْءَٰتُهُمَا وَطَفِقَا يَخْصِفَانِ عَلَيْهِمَا مِن وَرَقِ ٱلْجَنَّةِ ۚ وَعَصَىٰٓ ءَادَمُ رَبَّهُۥ فَغَوَىٰ

And they [i.e., Adam and his wife] ate of it, and their private parts became apparent to them, and they began to fasten over themselves from the leaves of Paradise. And Adam disobeyed his Lord and erred.

Translation: Saheeh International

Tafsir

So both of them Adam and Eve ate of it and their shameful parts were exposed to them that is the front private part of each became visible to the other as well as the other’s behind — both of these parts are called saw’a ‘shame’ because its exposure ‘shames’ yasū’u that person; …

Excerpt from Tafsir al-Jalalayn, commentary on 20:121, via Quran.com. The reader has the full commentary and 9 more tafsirs.