The words of Allah ta'ālā: (ٍإنَّهُ عَمَلٌ غَيْرُ صَالِح) in A | Dār At-Tawhīd

The words of Allah ta'ālā: (ٍإنَّهُ عَمَلٌ غَيْرُ صَالِح) in Ayah 46 of Surah Hūd are commonly translated as "indeed, his work/actions are unrighteous", referring to the son of Nūh (عليه السلام) after Nuh asked Allah ta'ālā about his son having been destroyed with the disbelievers, however according to at-Tabari, the correct  meaning (and this is linguistically more accurate) is "indeed, it (your question) is an unrighteous act." The first (more common) translation is based on a different reading (إنَّهُ عَمِلَ غَيْرَ صَالِحٍ) about which at-Tabari states that he doesn't know of any recitors from the major islamic cities who recited it this way except for those who came later on, and that the correct recitation is what the major cities have been upon: (إنَّهُ عَمَلٌ غَيْرُ صَالِح).

Then at-Tabari explains the verse, that it means: "indeed your question to me, what you asked me regarding your son, who opposed your deen and supported the people who ascribed partners to me, asking that he be saved from destruction, while my response to your (previous) du'ā has already passed (wherein you said:) 'do not leave upon the earth from among the disbelievers an inhabitant,' which has been carried out without excluding any of them, it (your question) is an unrighteous act."

So we see in the next ayah the natural response of Nūh (عليه السلام) :

[Noah] said, "My Lord, I seek refuge in You from asking that of which I have no knowledge. And unless You forgive me and have mercy upon me, I will be among the losers." - Hud 11: 47