Expostulator is a word that may not be commonly used in everyday language. It means to express strong disapproval or disagreement with someone, often in a forceful or agitated manner. Synonyms for this word include remonstrate, argue, admonish, protest, chide, rebuke, lecture and reprimand. These words can be used interchangeably depending on the context and degree of severity in which the disapproval is being expressed. Each of these synonyms has their own subtle difference in connotation and tone, but they all convey a level of dissatisfaction or disagreement with the situation or person at hand.