[1] : The Collaborative International Dictionary of English v.0.48

nix \nix\, n.; fem. nixe. g. cf. 1st nick. teut. myth.
   one of a class of water spirits, commonly described as of a
   mischievous disposition.
   1913 webster

         the treacherous nixes who entice men to a watery death.
                                                  --tylor.
   1913 webster
see also:
nixe nick 

[2] : WordNet (r) 2.0

nix
     n : a quantity of no importance; "it looked like nothing i had
         ever seen before"; "reduced to nil all the work we had
         done"; "we racked up a pathetic goose egg"; "it was all
         for naught"; "i didn't hear zilch about it" syn: nothing,
          nil, nada, null, aught, cipher, cypher, goose
         egg, naught, zero, zilch, zip
see also:
nothing nil nada null aught cipher 
cypher goose egg naught zero zilch 
zip 

[3] : Moby Thesaurus II by Grady Ward, 1.0

92 moby thesaurus words for "nix":
   davy, davy jones, neptune, nereid, oceanid, oceanus, poseidon,
   thetis, triton, abnegation, aught, cipher, contradiction,
   declension, declination, declinature, declining, denial,
   deprivation, disagreement, disallowance, disclaimer, disclamation,
   disobedience, dissent, fat chance, forget it, fresh-water nymph,
   goose egg, holding back, kelpie, kill, limniad, man fish, mermaid,
   merman, nada, naiad, naught, nay, naysaying, negation, negative,
   negative answer, negative attitude, negativeness, negativism,
   negativity, nichts, nihil, nil, nit, nixie, no, no sirree,
   no such thing, no way, nonacceptance, noncompliance, nonconsent,
   nonobservance, nope, not a chance, not much, nothing,
   nothing at all, nothing doing, nothing on earth, nothing whatever,
   ocean nymph, recantation, refusal, rejection, repudiation,
   retention, sea nymph, sea-maid, sea-maiden, siren, thing of naught,
   thumbs-down, turndown, under no circumstances, undine,
   unwillingness, water god, water spirit, water sprite, wind,
   withholding, zero, zilch

Nix >> N Words
Nix, definition of term: Nix
nix_pag1.html