Caught on the hop
Meaning
Surprised or unprepared.
Usage
Used when someone is unexpectedly thrown off guard.
Origin & History
Origins and dates here are approximate summaries. Many idioms have disputed or unknown origins, and not every date has been checked against a historical dictionary, so treat specific dates and stories as a starting point rather than a citation.
Horse racing phrasing for being unready when the starter gun fires.
British idiom now used worldwide.