“Then He will leave it” — meaning the earth — “a level plain” (qāʿan ṣafṣafā). The qāʿ is that which bears no trace, and the ṣafṣaf is the level land upon which there is no vegetation.
﴿فيذرها﴾ يَعْنِي: الأَرْض ﴿قاعا صفصفا﴾ الْقَاعُ: الَّذِي لَا أَثَرَ عَلَيْهِ، وَالصَّفْصَفُ: الْمُسْتَوِيَةُ الَّتِي لَيْسَ عَلَيْهَا نَبَات