What is "al-mutaffifin"

Sūrat al-Muṭaffifīn (, “The Defrauders”) is the eighty-third sura of the Qur'an with 36 ayat. Ibn Abbas is known for his knowledge of traditions as well as his critical interpretation of the Qur'an. From early on, he gathered information from other companions of Muhammad and gave classes and wrote commentaries. According to him "When the Prophet Muhammad came to Al-Madinah, they were the worst people in weights and measures. Then Allah, Glorious is He revealed: "Woe to the Mutaffifun (those who give less in measure and weight)", and they were fair in weights and measures after that. According to Abdullah ibn Masud, Muhammed used to recite two equal surahs in one rak'ah; he would recite (for instance) An-Naziat (79) in one rak'ah, surahs al-Mutaffifin (83) and Sūrat al-ʿAbasa (80) in one rak'ah.