catch napping

Idioms  

1. Surprise, take unawares. This term is often used in the passive, as in The United States was really caught napping the day the Japanese bombed Pearl Harbor. It originated in the mid-1500s as to be taken napping. Also see under off guard.

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Example Sentences

Frank Bird was a pretty hard fellow to catch napping, he usually had his eyes open, and especially when he knew there was danger around.

From The Aeroplane Boys Flight A Hydroplane Roundup by Langworthy, John Luther

But he was one of those wary old watch-dogs who are hard to catch napping.

From The Chouans by Wormeley, Katharine Prescott