not know what hit you
US /nɑt noʊ wʌt hɪt ju/
UK /nɑt noʊ wʌt hɪt ju/

1.
niet weten wat je overkomt, volledig verrast zijn
to be completely surprised or overwhelmed by something, often something negative or sudden
:
•
When the market crashed, many investors didn't know what hit them.
Toen de markt crashte, wisten veel beleggers niet wat hen overkwam.
•
The boxer landed a punch so fast, his opponent didn't know what hit him.
De bokser gaf zo'n snelle stoot dat zijn tegenstander niet wist wat hem overkwam.