The antonyms for the phrase "leaving defenseless" include "protecting," "defending," "shielding," "guarding," "preserving," "securing," "watching over," "supporting," and "fortifying." These words describe actions taken to ensure the safety and security of someone or something, rather than leaving them vulnerable to harm. By protecting individuals or objects, one can reduce the risk of harm or danger, providing an environment of security and peace. These antonyms are essential in creating a safe and secure world for all to live in, ensuring that all people and things are protected and safeguarded from all threats.