The word nithing also occurs as niding in modern english. It comes from the Old Norse niðingr and Old English niðing. According to the OED (Shorter OED, 3rd ed, 1959) the meaning is "A vile coward; an abject wretch; a villain of the lowest type". Webster's Revised Unabridged Dictionary (1913) gives the definition "A coward; a dastard; -- a term of utmost opprobrium."