knock something on the head
US /nɑk ˈsʌm.θɪŋ ɑn ðə hɛd/
UK /nɑk ˈsʌm.θɪŋ ɑn ðə hɛd/

1.
終止某事, 放棄計劃
to stop doing something or to put an end to a plan or activity
:
•
We need to knock this project on the head before it costs us any more money.
我們必須終止這個項目,以免它花費我們更多的錢。
•
I decided to knock my plans on the head and stay home instead.
我決定放棄我的計劃,待在家裡。