Musannaf Ibn Abi Shayba 22:76

Waki’ narrated to us, from Thabit, from Abu Safiyyah, from an old man whose kunya was Abu ‘Abd al-Rahman, from Ibn ‘Abbas, who said: "Zanim" (is) the ignoble one who is attached (to a people). Then he recited this verse: "A zanim whom men claim as an addition, just as the trotters are added to the width of a hide."