be caught napping

1. Literally, to be discovered sleeping when one is not supposed to be. The security guard was caught napping at his post, so they fired him. The headmaster's son was caught napping on the job? Oh, great—who's going to reprimand him? Yes, I was caught napping in class, but it's just because I pulled an all-nighter last night.

2. By extension, to have one's inattention exploited or capitalized on by someone else. The other team scored because our defensive tackle was caught napping. This is a highly competitive industry. You can't be caught napping, or you'll fall behind. The thieves were able to steal thousands in merchandise—they must have known when the guards could be caught napping.

be caught napping

If someone is caught napping, they suffer a disadvantage by not being prepared for something when it happens. The security services were clearly caught napping and their response was therefore inadequate. European firms have been caught napping. As a result, they barely control one-tenth of the world market. Note: `Napping' means the same as sleeping or dozing.

napping, to be caught/catch

To be surprised off guard, taken unawares. This term began life in the sixteenth century as to be taken napping. “Take Nappynge as Mosse toke his Meare” was the title of a 1569 ballad. The term was included in John Ray’s proverb collection of 1670, in which Ray commented, “Who this Moss was is not very material to know. I suppose some such man might find his mare dead, and taking her to be only asleep, might say, ‘Have I caught you napping?’” Yet Shakespeare and other sixteenth-century writers used the phrase in the modern sense of taking someone unawares; “Nay, I have ta’en you napping, gentle love,” Tranio says to Bianca (The Taming of the Shrew, 4.2).