The adjective importunate describes a plea that is so persistent or demanding that it becomes annoying. You can use the noun importunity to describe an example of this kind of pleading. You might ask for a bite of your friend's dessert with importunity, moaning about how hungry you are and how deliciously fudgy her chocolate cake looks. The root of importunity is the Latin importunitatem, which means "unsuitableness or incivility," and comes from importunus, "unfit or troublesome."