'insensate' originates from Latin, specifically the past participle form 'insensatus', where 'in-' meant 'not' and 'sensus' (from 'sentire') meant 'feeling'.

'insensatus' passed into Late Latin and then into English (via Middle English/Modern Latin usage) as 'insensate' with similar form and meaning.

Initially it meant 'not feeling' (physically insensible); over time it broadened to include 'lacking moral or emotional feeling' and 'senseless' in modern English.