The idiom "backroom boy(s)" refers to someone who works behind the scenes or in a back room, usually performing tasks that are not directly related to the main business or operations of an organization.

The idiom "vent spleen" means to express anger, frustration, or resentment. It can also mean to complain or criticize openly and vocally.

The idiom "it’s better to be safe than sorry" means that it is better to take precautions or take action to avoid negative consequences, rather than waiting and regretting not taking action after the fact. It emphasizes caution and foresight, rather than relying on luck or chance.

The idiom "all Greek to me" means that something is so difficult or unfamiliar to me that I cannot understand it or make sense of it. It is a figurative expression used to express confusion or ignorance about a particular topic.

This idiom refers to a collection of all the idioms or phrases that are commonly used in a language, typically for expressing emotions, beliefs, or cultural values.