pour cold water on

pour cold water on (something)

To discourage or deter someone from doing something; to make something seem less appealing or reduce someone's enthusiasm for something. News of unrest in the area really poured cold water on our plans to vacation there. Slashing your employees' benefits is a great way to throw cold water on their plans to stick with your company.
See also: cold, on, pour, water
Farlex Dictionary of Idioms.

pour cold water on something

 
1. Lit. to douse something with cold water. Pour cold water on the vegetables to freshen them. I poured cold water on my head to cool myself off.
2. and dash cold water on something; throw cold water on something Fig. to discourage doing something; to reduce enthusiasm for something. (Alludes to cooling passion with cold water.) When my father said I couldn't have the car, he poured cold water on my plans. John threw cold water on the whole project by refusing to participate.
See also: cold, on, pour, water
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

pour cold water on

Also, throw cold water on. Discourage or deter, as in Cutting my year-end bonus poured cold water on my loyalty to the company, or Hearing about the outbreak of cholera threw cold water on our plans to visit Bolivia. This term, with its image of putting out a fire with water, at one time meant "defame" or "slander"; the modern meaning dates from about 1800.
See also: cold, on, pour, water
The American Heritage® Dictionary of Idioms by Christine Ammer.

pour (or throw) cold water on

be discouraging or negative about a plan or suggestion.
1998 New Scientist When I put it to…the health minister, that perhaps all clinical trial results should be published, she threw cold water on the idea.
See also: cold, on, pour, water
Farlex Partner Idioms Dictionary

pour/throw cold ˈwater on something

(informal) discourage or try to prevent a plan, etc. from being carried out; be unenthusiastic about something: I’ve had lots of ideas about how to improve sales but my manager pours cold water on all my suggestions.
See also: cold, on, pour, something, throw, water
Farlex Partner Idioms Dictionary
See also:
  • (someone or something) promises well
  • accompanied by
  • accompanied by (someone or something)
  • accompany
  • a fast talker
  • a slue of (something)
  • (have) got something going (with someone)
  • a ghost at the feast
  • a/the feel of (something)
  • (I) wouldn't (do something) if I were you