viciousness n. + Add to list US //ˈvɪʃəsnɪs// UK //vˈɪʃəsnəs// vi·cious·ness SynonymsEtymology Synonyms brutalityferociousnesssavageryOriginMEviciousnesse→ENviciousness From Middle English viciousnesse; equivalent to vicious + -ness.