'aspersor' originates from Latin, specifically the word 'aspersor', where the root 'aspergere' meant 'to sprinkle' or 'to scatter'.

'aspersor' passed into Old French (as a form like 'asperseur') and Middle English (related forms such as 'asperser'), and eventually became the modern English agent noun 'aspersor' (with a plural 'aspersors').

Initially, it referred literally to 'one who sprinkles' (water or similar). Over time, via the figurative sense of 'to besprinkle' with blame or dirt, it also came to be used (rarely) of someone who spreads slander or aspersions.