Antonyms for the phrase "catching off guard" include being prepared, ready, alert, vigilant, and attentive. These antonyms reflect a sense of heightened awareness and readiness, suggesting that the person in question is fully equipped to handle unexpected situations. For example, someone who is prepared might have a contingency plan in place to deal with unexpected changes, while someone who is alert has a keen eye for spotting potential problems before they arise. By contrast, being caught off guard implies a sense of surprise or unpreparedness, which can be a liability in many situations. As such, it pays to be vigilant and ready for whatever comes your way.