The opposite of being on alert is being off-guard or unaware. Alertness refers to a state of watchfulness or readiness for potential danger, while its antithesis denotes a lack of vigilance, which could expose an individual to risks. Those who are off-guard or complacent may fail to detect threats or anticipate impending concerns. Conversely, individuals who maintain a state of mindfulness and readiness, even in the absence of an apparent threat, are better equipped to navigate unexpected circumstances. Heightened alertness, however, can also lead to anxiety or hyper-vigilance. Therefore, it is crucial to strike a balance between being vigilant and being relaxed, depending on the situation.