'apepsy' originates from Greek, specifically the word 'apepsia', where the prefix 'a-' meant 'without' and 'pepsis' meant 'digestion'.

'apepsy' changed from the medical Greek/Latin word 'apepsia' (attested in medical writings) and entered English medical usage in early modern/19th-century texts as 'apepsy' or 'apepsia'.

Initially it meant 'lack of digestion' or 'failure of digestion'; over time the meaning has remained essentially the same but the term has become rare and largely replaced by 'dyspepsia' or 'indigestion'.