Caustical is a term often used to describe something that is extremely critical or harshly sarcastic in nature. However, there are several synonyms for this word that can help bring variety to your communication style. One synonym is acerbic, which refers to a sharp or biting remark. Another alternative is scathing, which indicates a severely critical or damaging comment. You could also use cutting, meaning a remark that is intended to hurt or wound emotionally. For a more subtle replacement, you could opt for sardonic, which implies dry mockery or disdain. By utilizing these synonyms, you can add depth to your expressions and convey your message with precision.