ٱلَّذِينَ Those ضَلَّ is lost سَعْيُهُمْ their effort فِى in ٱلْحَيَوٰةِ the life ٱلدُّنْيَا (of) the world وَهُمْ while they يَحْسَبُونَ think أَنَّهُمْ that they يُحْسِنُونَ (were) acquiring good صُنْعًا (in) work ١٠٤
[They are] those whose effort is lost in worldly life, while they think that they are doing well in work."
— Come To Light