'agametically' originates from New Latin, specifically the adjective 'agametic', where the prefix 'a-' meant 'not' and 'gamete' comes from Greek 'gamētēs' meaning 'spouse' or 'marriage' (used in biology to mean 'reproductive cell').

'agametically' was formed from the New Latin/Neo-Latin adjective 'agametic' (from a- + gamete) and the English adverbial suffix '-ally' (from Old French/Latin '-alis'), yielding the modern English adverb 'agametically'.

Initially it meant 'without gametes' in a biological sense, and this core meaning has been retained into modern usage as 'in a manner without gametes (asexually)'.