'counter-plethoric' is a compound formed from English 'counter-' and 'plethoric'; 'counter-' ultimately derives from Latin 'contra' meaning 'against', and 'plethoric' derives from Greek 'plēthōra' meaning 'fullness'.

'plethoric' entered English via Latin/Greek forms related to 'plethora' (Greek 'plēthōra') and came to mean 'overfull' or 'excessive' (especially of blood); 'counter-' has long been a productive English prefix (from Old French 'contre', Latin 'contra') used to form opposites, and the compound 'counter-plethoric' is a later English formation applying 'counter-' to 'plethoric' (primarily modern/19–20th century in technical or rhetorical usage).

Originally, 'plethoric' described physiological overfullness (notably of blood); 'counter-plethoric' originally referred to measures that reduced such bodily excess, and it has since broadened in some contexts to mean opposing excess more generally (e.g., stylistic excess).