Insecure can be defined as lacking confidence or not feeling safe or protected. Its antonyms are confident, assured, certain, secure, and safe. Confidence is the opposite of insecure because it signifies a strong belief in oneself and one's abilities. Assured is the opposite because it indicates trust and certainty in oneself or a situation. Certainty is the opposite because it suggests a lack of doubt or uncertainty. Secure and safe are opposites because they indicate protection and safety from harm or danger. All of these antonyms carry a strong positive connotation, which highlights the importance of feeling secure and confident in oneself and in the world around us.