'assagai' originates from Portuguese, specifically the word 'azagaia', where the root meant 'spear' or 'light throwing spear'.

'azagaia' entered Portuguese (and Spanish as 'azagaya') from contact with North African/Berber and Arabic languages; the word was borrowed into English in the 16th–18th centuries as 'assagai' or 'assegai'.

Initially it referred to the Portuguese/Spanish term for a light spear; the meaning in English has remained close to that original sense, denoting the African throwing or stabbing spear.