I. ˈniks noun
Etymology: German nichts nothing
Date: 1789
: nothing
II. transitive verb
Date: circa 1903
: veto , reject
the court nix ed the merger
III. adverb
Date: 1902
: no — used to express disagreement or the withholding of permission; often used with on
they said nix on our plan
IV. noun
Etymology: German, from Old High German nihhus; akin to Old English nicor water monster and perhaps to Greek nizein to wash
Date: 1833
: a water sprite of Germanic folklore