not know what hit (one)
not know what hit (one)
To be extremely shocked, surprised, or confused by something. When my father passed away, I just didn't know what hit me. With this new strategy, our opponents won't know what hit them.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
not know what hit you
be hit, killed, or attacked by someone or something without warning.Farlex Partner Idioms Dictionary © Farlex 2017
not know what ˈhit you
(informal) be so surprised by something that you do not know how to react: You should have seen his reaction! He didn’t know what had hit him! OPPOSITE: see something comingFarlex Partner Idioms Dictionary © Farlex 2017