When we use the phrase "a plague on someone," it implies that we wish harm or misfortune upon that person. However, there are other synonyms that can be used to convey the same sentiment. One such phrase is "curse on," which has a similar connotation of wishing ill on someone. "Damnation to" is another expression that can be used to convey the idea of a curse or condemnation. "Hex upon" is a more playful way of saying that we wish someone bad luck. And finally, "jinx on" is an expression that can be used when we want to express our desire for someone to fail or stumble. Ultimately, each of these phrases conveys the idea of wishing harm upon someone, but with slightly different nuances.