Aspergillum is an instrument that is primarily used in religious rituals to sprinkle holy water. There are many synonyms for the word aspergillum, such as sprinkler, censer, thurible, and hyssop. A sprinkler is an instrument that is commonly used to sprinkle water, and it is an excellent synonym for the aspergillum. A censer is also a synonym for the aspergillum, as it is an instrument used in religious ceremonies to dispense incense. Thurible, on the other hand, is a metal container used to burn incense, while hyssop is an herbaceous plant used for purification in religious ceremonies. These synonyms can be used in place of aspergillum, depending on the context.