Aspersion is a fun word in English.
It comes from the Latin word Spargere, which means “to scatter” or “to sprinkle”. Its most common definition is to insult or doubt somebody, as if you were “scattering” insults on them.
We typically use the word “cast” before it in a sentence. For example, I could say “after eating, he cast aspersions on the restaurant’s cleanliness”.
However, there’s also another use of the word.
Remember how Spargere in Latin could also mean “to sprinkle”? Well, in English the original meaning of the word “aspersion” was “a baptism by sprinkling water”. So, if you hear about some Christians who had a priest sprinkle water on their newborn, that’s called an aspersion.
This meaning is directly related to the other original meaning for “aspersion” in English: the sprinkling of Christ’s blood. Since baptism references Christ’s death and resurrection, it makes sense that we would use a similar word to describe it.