Jump on refers to the act of quickly criticizing or rebuking someone about something they have done or said. Synonyms that can be used instead of jump on include reprimand, berate, scold, criticize, admonish, upbraid, censure, chide, lambaste, and castigate. These words have different shades of meaning and can be chosen depending on the context in which they are used. Additionally, alternative phrases that can replace jump on include "call out," "take to task," "pull up," "correct," "lecture," and "remand." When speaking or writing, it is important to choose the most appropriate word or phrase that accurately conveys the intended meaning.