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

sickening \sick"ening\, a.
   causing sickness; specif., causing surfeit or disgust;
   nauseating. -- sick"eningly, adv.
   1913 webster
see also:
sick"eningly 

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

sicken \sick"en\, v. t. imp.  p. p. sickened; p. pr.  vb.
   n. sickening.
   1. to make sick; to disease.
      1913 webster

            raise this strength, and sicken that to death.
                                                  --prior.
      1913 webster

   2. to make qualmish; to nauseate; to disgust; as, to sicken
      the stomach.
      1913 webster

   3. to impair; to weaken. obs. --shak.
      1913 webster
see also:
sickened sickening 

[3] : WordNet (r) 2.0

sickening
     adj : causing or able to cause nausea; "a nauseating smell";
           "nauseous offal"; "a sickening stench" syn: nauseating,
            nauseous, noisome, loathsome, offensive, vile
see also:
nauseating nauseous noisome loathsome offensive vile 

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

60 moby thesaurus words for "sickening":
   abhorrent, abominable, bad, barfy, base, beastly, below contempt,
   beneath contempt, brackish, cloying, contemptible, crude,
   despicable, detestable, disgusting, execrable, fetid, forbidding,
   foul, fulsome, gross, hateful, heinous, high, icky, ignoble,
   loathsome, maggoty, malodorous, mawkish, mephitic, miasmal,
   miasmic, nasty, nauseant, nauseating, nauseous, noisome, noxious,
   objectionable, obnoxious, obscene, odious, offensive, overripe,
   poisonous, rancid, rank, rebarbative, repellent, repugnant,
   repulsive, revolting, rotten, spoiled, stinking, vile, vomity,
   weevily, yucky

Sickening >> S Words
Sickening, definition of term: Sickening
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