catch someone off guard

catch someone off guard

or

take someone off guard

COMMON If something catches you off guard or takes you off guard, it happens unexpectedly and you are not prepared to respond to it. Note: Your guard is the position that you get in when you are ready to defend yourself in sports such as boxing or fencing. I didn't know how to answer him. The question caught me off guard. I wasn't expecting him to pass the ball to me and it took me off guard.
See also: catch, guard, off, someone
References in periodicals archive ?
Catch someone off guard and show you mean business.
By then I decided to take it out hard and see if I could catch someone off guard.
It wasn't like she was wandering through Mothercare waiting to catch someone off guard.