'aspergation' originates from Latin, specifically the word 'aspergere,' where the elements 'ad-' (assimilated) meant 'to' or 'toward' and 'spargere' meant 'to scatter' or 'to sprinkle'.

'aspergation' passed through Medieval Latin as 'aspergatio' and was adopted into English with the modern form 'aspergation', retaining the sense of 'sprinkling'; the figurative sense ('casting aspersions') developed later by association with verbs like 'asperse'.

Initially, it meant 'the act of sprinkling' (often ritually). Over time it also acquired a figurative meaning of 'casting reproach or slander' (i.e., harming reputation).