Get cold feet (not do something because you get nervous): She wanted to sing at the concert but then she got cold feet.
Blow hot and cold (often change your opinion about something): I blow hot and cold about London. Sometimes I love it, sometimes I hate it.
Give someone the cold shoulder (not be friendly to someone): She gave him the cold shoulder after they broke up.
Leave someone cold (not impress someone): I'm afraid that film really left me cold.
Throw cold water on something (say an idea isn't good): Please don't throw cold water on my idea! Let me try it.
A cold snap (a short period of cold weather): We in the middle of a cold snap right now.
Be cold comfort (not be comforting): She wanted to win first prize, so coming fourth was cold comfort.
Be knocked out cold (be made unconscious): The boxer was knocked out cold.
Cold hard cash (money): Don't give me presents! I want cold hard cash!
In cold blood (of a crime, not at the moment of being angry or upset): He killed the man in cold blood.