The antonyms for the word 'un vigilant' are quite numerous as there are many terms that can be used to describe someone who is vigilant. The word vigilant means to be watchful, alert, and attentive. It is the opposite of neglectful, inattentive, and careless. Therefore, some of the antonyms for un vigilant would be observant, attentive, diligent, mindful, cautious, and watchful. A person who demonstrates these qualities is someone who is always aware of their surroundings and takes steps to protect themselves from danger. Being vigilant is an important quality to possess as it can mean the difference between safety and harm.