'iconoclastic' originates from Modern Latin and late Greek, ultimately from the Greek word 'eikonoklastēs', where 'eikon' meant 'image' and 'klastes' (from 'klaō') meant 'breaker'.

'eikonoklastēs' (Greek, literally 'image‑breaker') passed into Late Greek and Medieval Latin as 'iconoclastes'/'iconoclasticus' and later entered English as 'iconoclasm' and the adjective 'iconoclastic'.

Initially it referred specifically to people who physically destroyed religious images ('image‑breakers'); over time it broadened to mean those who attack or reject established beliefs, customs, or institutions.