'consistently-prohibited' is a compound built from 'consistently' (from 'consistent') and 'prohibited' (the past participle of 'prohibit'). 'Prohibit' originates from Latin, specifically the word 'prohibere', where 'pro-' meant 'in front of/before' and 'habere' meant 'to hold'.

'prohibere' passed into Old French and Late Latin forms and then into Middle English as 'prohibiten' or similar forms; from these medieval forms it developed into the modern English verb 'prohibit', with 'prohibited' as its past participle. 'Consistent' comes from Latin 'consistere' via Old French and Middle English; 'consistently' is its adverbial form.

Initially 'prohibere' carried the sense 'to hold back' or 'to keep away', and over time it specialized to the modern meaning 'to forbid (by authority)'; combining with 'consistently' gives the sense 'forbidden without exception' in contemporary usage.