"Be caught napping" is an idiomatic phrase which means to be caught off guard or unprepared. Synonyms for this phrase include "be taken by surprise," "be caught off guard," "be caught unaware," "be caught flat-footed," and "be caught out." Each of these synonyms implies that someone has been caught in a state of unpreparedness or inattentiveness. These phrases can be used in various contexts, such as in business, sports, or personal situations. It is always important to remain alert and prepared, so that you do not get caught napping when an unexpected situation arises.