Taken off guard is an expression commonly used to describe a situation where someone is caught unaware and unprepared. Synonyms for this phrase include caught off guard, caught by surprise, caught unawares, surprised, and blindsided. These words all convey a sense of being caught off balance or unprepared for whatever is happening. Other synonyms for taken off guard include caught in a vulnerable moment, ambushed, stunned, thrown off balance, and jolted. Each of these words conveys a slightly different nuance, but all refer to a situation where someone is unexpectedly caught off guard and must respond in a way that is not ideal.