The word "defend" means to protect or guard against harm or danger. Its antonyms are words that convey the opposite meaning. The first antonym is "attack," which means to cause physical or emotional harm to someone or something. The second antonym is "ignore," which means to pay no attention to or disregard someone or something. The third antonym is "surrender," which means to give up, abandon, or yield to a superior force or authority. The fourth antonym is "disengage," which means to withdraw from, detach, or dissociate oneself from a situation or relationship. Knowing these antonyms to "defend" can help in understanding the varying aspects of a situation involving protection or safety.