1 tr. affect with loathing or disgust.
2 intr. a (often foll. by for) show symptoms of illness (is sickening for measles). b (often foll. by at, or to + infin.) feel nausea or disgust (he sickened at the sight).
3 (as sickening adj.) a loathsome, disgusting. b colloq. very annoying.
Derivatives:
sickeningly adv.
Useful english dictionary. 2012.