'aposiopetic' originates from Greek, specifically the word 'aposiōpēsis' (ἀποσιώπησις), where the prefix 'apo-' meant 'away' and the root 'siōpē' meant 'silence'.

'aposiopetic' changed from the Greek noun 'aposiōpēsis' into Late Latin/Medieval Latin 'aposiopesis', was borrowed into English as 'aposiopesis' (the noun), and the adjective was formed in English by adding the adjectival suffix '-etic' to produce 'aposiopetic'.

Initially it meant 'the act of becoming silent' or 'falling silent', but over time it evolved to mean 'relating to or exhibiting a sudden breaking off in speech (for rhetorical effect)'.