The word "pester" can be defined as annoying or bothering someone persistently. However, there are several synonyms for "most pester," including "harass," "torment," "irritate," "provoke," "aggravate," "bother," "nag," "plague," "vex," "badger," and "hound." Each of these words can be used to describe someone who persistently annoys or bothers another person through their actions or words. In some cases, these synonyms can be part of a pattern of bullying or harassment, and it is important to recognize when someone's behavior crosses a line and becomes unacceptable.