'putrefactive' originates from Latin, specifically from the verb 'putrefacere' (and its past participle forms such as 'putrefactus'), where 'putre-' meant 'rotten' and 'facere' meant 'to make'.

'putrefacere' produced Late/Medieval Latin forms like 'putrefactus' and adjective formations (e.g. 'putrefactivus'), which later entered English as 'putrefactive' via learned borrowings from Latin (and through scholarly/medical Latin usage).

Initially it was tied to the literal sense 'to make rotten' or 'having been made rotten'; over time it came to be used adjectivally in English to mean 'causing or characterized by putrefaction/decay', largely retaining that original sense.