'primitively' originates from Latin, specifically the word 'primitivus', where 'primi-' meant 'first' and the suffix '-tivus' formed adjectives.

'primitivus' passed into Late Latin and Old French as 'primitif' and then into Middle English as 'primitive'; the adverb 'primitively' was formed in English by adding the suffix '-ly' to the adjective 'primitive'.

Initially it meant 'first' or 'original' (related to order or beginning), but over time it came to mean 'simple, undeveloped, or early in development', and the adverb now means 'in a simple or undeveloped way'.