cool as a cucumber
MEANING: calm, not nervous or anxious
He is always as cool as a cucumber and never worries about anything.
MEANING: a very lazy person
He is a real couch potato and just sits around watching TV and staying indoors all day.
cream of the crop
MEANING: best of a group, the top choice
The company is well-known as a good place to work and is always able to hire the cream of the crop of university graduates.
cry over spilt milk
MEANING: cry or complain about something that has already happened
Don’t cry over spilt milk. The past is past and you can’t do anything to change it.
cup of tea
MEANING: something one enjoys or does well
Going to art galleries is not my cup of tea so I think that I will stay home this evening and not go with you.
MEANING: a question or argument that is controversial and difficult to settle
The issue of building the nuclear power plant is a real hot potato for the local town
out to lunch
MEANING: crazy, mad
She is totally out to lunch and you should never believe what she tells you.
piece of cake
MEANING: a task that is easily accomplished
It was a piece of cake. I had everything done before lunch this morning.