Meaning – to put an end to something, to terminate a project / situation
In Context – I’m pulling the plug on this marketing strategy, it’s just not working.
Origin – This is an American idiom which originated in the 19th century. Plug has a second meaning in English. It is also the object used to prevent water escaping from a sink (a stopper in US English). In 19th century America, toilets had plugs so to flush a toilet, you needed to pull the plug.
Opposite Idiom – to give something the red light