The idiom "John Doe" is used to refer to an unknown person or someone whose identity is not known. It can be used to describe someone who is a stranger, a random person, or someone who is unidentified in a situation.

The idiom "low hanging fruit" refers to something that is easy to access or achieve, often because it is close to the ground or already within reach. It can also refer to something that requires little effort or skill to accomplish.

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 "give it a whirl" is used to encourage someone to try something new or different for the first time. It implies that there might be some risk involved, but also suggests that the outcome could be positive.

The idiom "to the core" means to do something sincerely, deeply, or completely. It suggests that a person is being honest and genuine in their actions or words, and that they are not just putting on a show or pretending to be someone else.