English Reference
Phrasal verb

knock up

phrasal verb.
B2 Upper Intermediate Oxford

phrasal verb.to wake someone by knocking on their door — often used in informal British English.

phrasal verb.to wake someone by knocking; also used informally to mean 'to create or produce something quickly' (e.g., 'knock up a report'). Marked British informal / slang.


SIMPLE

He knocked up his friend at 7 AM.

CONTEXTUAL

She had to knock up her roommate because they were late for work.

COMPLEX

The journalist knocked up a detailed report in under an hour, impressing the editor.

Usage

typically followed by a person or thing being created or woken.

Teaching tip

contrast with 'wake up' (more direct) and 'produce' (formal alternative); note the informal use of 'knock up' meaning 'create quickly' is limited to British English.

Pitfall
He knocked up.He knocked up his friend.

the phrasal verb requires an object to indicate who or what is being knocked up

Particles
up
Separability
inseparable
Pattern
knock + up + object
This entry
Level B2 · Upper Intermediate
Updated