not know what hit one
Proposed by a contributor, not yet supported by evidence.
Meaning · English
be completely surprised or shocked by something
Literally: not know what struck one
Where it’s used:
Used
Widespread English
Examples
He didn't know what hit him when the company suddenly went bankrupt.
AI-drafted example auto-approved by rule (illustrative, not a corpus attestation)
Sources & notes
Listed in Wiktionary’s “English idioms” category (retrieved 2026-07-29); definition pending editorial review. Definition drafted by AI (@cf/meta/llama-3.3-70b-instruct-fp8-fast) and auto-approved by rule on 2026-07-31; pending editor spot-check.
Common questions
What does “not know what hit one” mean?
be completely surprised or shocked by something Literally: not know what struck one
Is “not know what hit one” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.