innocent: [14] Someone who is innocent is literally ‘harmless’. The word comes, partly via Old French, from Latin innocēns, an adjective formed with the negative prefix in- from the present participle of nocēre ‘harm’ (source of English nuisance) – hence, ‘not harming’. The slight semantic shift from ‘not harming’ to ‘blameless, guiltless’ took place in Latin. => nuisance[innocent etymology, innocent origin, 英语词源]