Etymology
From Middle English nithing, nithinc, nything, nythyng, nythynge, niþinge, nyþing, nyþyng, Early Middle English niðing, niþinc, niþincke (“coward, wretch; good-for-nothing; term of address for a boy or lad; stingy or miserly person; niggardly, miserly, stingy”), from Late Old English nithing, Old English niðing, nīþing (“coward; wretch; outlaw, villain”), from a North Germanic language, from Proto-Germanic *nīþą (“envy; hate; malice”) (from Proto-Indo-European *neyH- (“to be angry”)) + *-ingō, *-ungō (suffix forming gerund nouns from verbs).
The English word is cognate with Danish nidding, Late Latin nidingus, nithingus, Middle High German nīdinc, nīdunc (modern German Neiding (“(archaic) one who is envious”)), Old Norse níðingr (Icelandic níðingur (“scoundrel, rascal”), Norwegian niding),