O.E. nied (W.Saxon), ned (Mercian) "necessity, compulsion, duty," originally "violence, force," from P.Gmc. *nauthis (cf. O.N. nauðr, O.Fris. ned, M.Du. nood, Ger. Not, Goth. nauþs "need"), probably cognate with O.Pruss. nautin "need," and perhaps with O.C.S. nazda, Rus. nuzda, Pol. nedza "misery, distress," from PIE *nau- "death, to be exhausted." The more common O.E. word for "need, necessity, want" was ðearf, but they were connected via a notion of "trouble, pain," and the two formed a compound, niedðearf "need, necessity, compulsion, thing needed." Nied also may have been infl. by O.E. neod "desire, longing," which was often spelled the same. Common in O.E. compounds, e.g. niedfaru "compulsory journey," a euphemism for "death;" niedhæmed "rape," the second element being an O.E. word meaning "sexual intercourse;" niedling "slave." Meaning "extreme poverty, destitution" is from c.1200. The verb is O.E. neodian "be necessary," from the noun. Phrase the needful "money" is attested from 1774. The adj. phrase need-to-know is attested from 1954.