The idiom "red zone" refers to a high-risk or dangerous area. It can be used to describe a physical location, such as a war-torn region or an area with high crime rates, or a metaphorical location, such as a person's temperament or a situation that poses a risk.

The idiom "fair-weather friend" refers to someone who is friendly and supportive only when things are going well or it's convenient. They tend to disappear or become distant when things get difficult or challenging.

The idiom "bury the hatchet" means to end a conflict or disagreement, or to make peace between two parties who have been at odds. It suggests that the past is buried and forgotten, and that both sides are ready to move forward together in harmony.

The idiom "de facto" means "in practice or actuality" or "in effect, although not officially recognized." It refers to a situation where something is happening or being done even though it may not be legally binding or official.

The idiom "young blood" refers to a new person who is inexperienced or just starting out in something, such as beginning a job or entering a certain field. It can also refer to someone who is energetic and full of enthusiasm for life.