'apaesthetize' is formed in English from the combining elements 'a-' (a variant prefix) + 'aesthetize', where 'aesthetize' ultimately derives from Greek 'aisthētikos' (from 'aisthesthai' meaning 'to perceive'); the productive English suffix '-ize' makes it a verb.

'aesthesis' and related forms come from Greek 'aisthēsis' ('
perception, sensation
'), passed into Late Latin/Medieval Latin as 'aestheticus' and then into modern European languages as 'aesthetic'; English later formed the verb 'aesthetize' (use of '-ize'), and 'apaesthetize' was coined by prefixing 'a-' to create a sense of removing or dulling aesthetic response.

Initially the Greek root referred to simple 'perception' or 'sensation,' but in modern English the derived forms have specialized to concern aesthetic perception and judgment; 'apaesthetize' specifically developed the meaning 'to make insensitive to aesthetic qualities.'