blindside

blindside /ˈblaɪndˌsaɪd/ verb
blindsides; blindsided; blindsiding
blindside
/ˈblaɪndˌsaɪd/
verb
blindsides; blindsided; blindsiding
Britannica Dictionary definition of BLINDSIDE
[+ object] US
1 
: to hit (someone who is facing in another direction) suddenly and very hard
2 
: to surprise or shock (someone) in a very unpleasant way