'antiplethoric' originates from English, specifically formed from the combining prefix 'anti-' + 'plethoric', where 'anti-' meant 'against' and 'plethoric' meant 'excessively full (especially of blood).'

'plethoric' comes from Medieval Latin/Latin medical usage (e.g. Latin 'plethoricus') ultimately from Greek 'plēthōrē' (πληθώρα) meaning 'fullness'; English formed 'plethoric' and later compounds such as 'antiplethoric' appeared in medical contexts by adding the prefix 'anti-'.

Initially it meant 'against fullness' in a specifically medical sense (remedies to reduce bodily excess); over time it has remained rare and is now used chiefly as a literary or historical adjective meaning 'countering excess' more generally.