“Capital error” means a grave or serious mistake, often one with major consequences.
“To speak by the cards” means to speak clearly, frankly, and without deception.
“To cave in” means to give up, collapse, or surrender after resistance.
“Child’s play” means something very easy to do, not requiring much effort.
“Claybrained” describes a person who is dull-witted or very stupid.
A “turncoat” is someone who changes allegiance or loyalty, especially for personal gain.
A “cock and bull story” is an unbelievable or absurd tale made up to mislead.
“That cock won’t fight” means that a plan, excuse, or argument will not work or be accepted.
“To have cold feet” means to suddenly lose courage or confidence to do something planned.
“To tread on one’s corns” means to offend or hurt someone’s feelings, often unintentionally.