'mortality-affirming' originates from Modern English as a compound of 'mortality' and the present participle 'affirming'. 'mortality' comes from Latin 'mortalis'/'mortalitas', where 'mors/mort-' meant 'death'; 'affirming' comes from Latin 'affirmare', where 'ad-' (expressed in some reflexes) meant 'to' or intensifier and 'firmare' meant 'to make firm/confirm'.

'mortality' developed from Latin 'mortalis' through Old French and Middle English into the Modern English noun 'mortality', while 'affirming' derives from Latin 'affirmare' via Old French/Medieval Latin into English 'affirm' + present participle '-ing'. The hyphenated compound 'mortality-affirming' is a recent Modern English formation combining those elements.

Initially, the component words referred separately to 'death' ('mortality') and 'to assert or confirm' ('affirm'). Over time the compound has come to mean 'positively acknowledging or embracing mortality' rather than simply the juxtaposition of the two words.