The idiom "damp squib" refers to an event, person, or idea that fails to live up to expectations or is a disappointment. It can also mean something that is uninteresting or lacks excitement.

The idiom "have designs on" means to have plans or intentions for someone or something. It suggests a desire to control or influence the person or thing in question.

The idiom "rough diamond" refers to a person who has good potential or qualities but needs work or refinement before they can be fully realized. It can also refer to a person who is rough around the edges, meaning they may have some flaws or shortcomings that need to be addressed.

The idiom "the lion's den" refers to a place that is very difficult or dangerous to enter, escape from, or survive in. It can also refer to a situation where someone is confronted with a daunting or formidable challenge.

The idiom "all in a day's work" means that something can be done or accomplished easily and efficiently within a regular working day. It implies that the task is not particularly challenging or difficult, and it can be completed in a short amount of time.