'antimystical' originates from Modern English, specifically a compound of 'anti-' and 'mystical', where 'anti-' derives from Greek 'antí' meaning 'against' and 'mystical' derives from Greek 'mystikos' meaning 'secret' or 'mystical'.

'mystical' passed into English via Latin 'mysticus' and Old French 'mystique', ultimately from Greek 'mystikos'; 'anti-' comes from Greek 'antí'. The Modern English compound 'antimystical' was formed by combining these elements (notably in the 19th–20th century) to express opposition to mysticism.

Initially, Greek 'mystikos' referred to 'secret' or 'initiation rites' and then to religious or spiritual 'mystery' or 'mystical' experiences; over time 'mystical' came to mean 'relating to spiritual mystery', and 'antimystical' evolved to mean 'against such beliefs or practices'.