Tafsir of An-Najm 53:61

وَأَنتُمْ سَامِدُونَ (while you are engaged in vain play?....53:61). Samidun is the plural of |"samid|" from the root word sumud which literally denotes to be heedless. Samidun is used in the sense of ghafilun, meaning unmindful. Some of the Imams have interpreted the word sumud to mean to sing. That meaning can equally fit or apply in this context.