The idiom "bosom friend" refers to a person who is extremely close to you, someone you trust and confide in with your deepest secrets. It suggests a level of intimacy that goes beyond mere friendship and into the realm of emotional support and connection.

Achilles heel is an idiom that refers to a person's weakness or vulnerability, often something that they are not aware of themselves. The idiom comes from the story of Achilles, who was invincible in battle except for his heel, which was vulnerable to attack.

The idiom "strike while the iron is hot" means that it's a good time to take advantage of an opportunity or to do something when conditions are favorable. This phrase suggests that if you don't act quickly, the opportunity may pass by and become unavailable.

The idiom "in the red" refers to a situation or financial position that is in debt, with negative equity or loss. It can also indicate danger or risk, as in being in an area or situation where there is potential harm.

The idiom "no love lost" means that there is no need to worry about any negative consequences of an action or decision, as the outcome will not be dire. It suggests that things will work out in the end and that there is no harm done.