Undueness refers to something that is inappropriate or undeserved. There are several synonyms for this word that can be used interchangeably depending on the context. One such synonym is injustice, which refers to a situation or activity that is unfair or morally wrong. Another synonym for undueness is impropriety, which refers to behavior that is not considered appropriate or acceptable. Inappropriate, unsuitable, and unacceptable are also common synonyms that can be used to describe undueness. These words all reflect a lack of suitability or appropriateness and suggest that something is incorrect or unjustifiable. Ultimately, the choice of synonym will depend on the specific context in which the term is being used.