- necessary
- mid-14c. (n.), late 14c. (adj.), from L. necessarius, from necesse "unavoidable, indispensable," originally "no backing away," from ne- "not" + cedere "to withdraw, go away, yield" (see cede). Necessary house "privy" is from c.1600. Necessity (late 14c.) is from O.Fr. necessité, from L. necessitatem (nom. necessitas) "compulsion, need for attention." Necessitate is first attested 1620s.