AMENTIA Meaning of AMENTIA in English [ eɪ'mɛnʃə , ə- ]■ noun Medicine, dated severe congenital mental disability.OriginME: from L., lit. 'madness', from amens , ament- 'mad', from a- 'without' + mens 'the mind'. Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004