The word "harriest" means to harass or bother someone persistently. Some synonyms for this word include pester, plague, vex, irritate, and annoy. These words all describe actions of bothering someone in a way that can be frustrating and annoying. Other words that could also be used to describe the same meaning would be agitate, bother, badger, nag, and hound. It is important to remember that using synonyms can add variety to your writing, but you should make sure that the synonym accurately conveys the intended meaning of the word you are replacing.