'demystify' originates from English formation using the Latin prefix 'de-' (meaning 'remove') combined with the verb 'mystify', which itself comes from French and Latin roots.

'mystify' came into English from French 'mystifier', from Late Latin 'mystificare', ultimately from Greek 'mystikos' related to 'mystery'; 'demystify' was formed later in English by adding the prefix 'de-' to 'mystify'.

Initially related to initiation into mysteries or causing bewilderment (as in older senses of 'mystify'), the sense shifted toward 'making mysterious' and then to the modern sense of 'removing mystery' or 'explaining' when formed with the prefix 'de-'.