• oour cold water on,
• lour cold water on,
• -our cold water on,
• 0our cold water on,
• piur cold water on,
• pkur cold water on,
• plur cold water on,
• ppur cold water on,
• p0ur cold water on,
• p9ur cold water on,
• poyr cold water on,
• pohr cold water on,
• pojr cold water on,
• poir cold water on,
• po8r cold water on,
• po7r cold water on,
• poue cold water on,
• poud cold water on,
• pouf cold water on,
• pout cold water on

The adverb form of "pour cold water on" would be "dismissively" or "disparagingly", depending on the context.

The adjective form of the phrase "pour cold water on" is "discouraging".