The idiom "batten down the hatches" means to prepare for a difficult or dangerous situation by taking necessary precautions and being ready for whatever may happen. It is often used when one is about to face an uncertain event, such as a storm or a crisis.

The idiom "eat words" means to swallow one's words or to retract something that was previously said. It is often used to describe a situation where someone has spoken impulsively or incorrectly and is now forced to admit their mistake by eating their words.

The idiom "make common cause" means to join forces or combine efforts for a common goal or purpose. It can also mean to act in concert or unison, to coordinate one's activities with another person or group for a shared objective.

The idiom "turn back on" means to reverse or undo a previous decision, action, or behavior. It can also refer to rejecting or refusing something, such as a request or proposal.

The idiom "bon appetit" is used to express a wish of enjoyment, satisfaction or success in what is about to be eaten or experienced. It can also be used as an expression of encouragement or best wishes before embarking on a new journey or endeavor.