What does the idiom spell it out mean?

The idiom "spell it out" means to explain something in a very clear and detailed way, leaving no room for misunderstanding. It implies that the person being addressed might not be understanding something, and needs a simple and straightforward explanation.

Here are some examples of how "spell it out" is used:

* "I'm not sure I understand. Can you spell it out for me?"

* "The teacher spelled out the instructions so that everyone would understand."

* "I don't want to spell it out for you, but you need to be more responsible."

Essentially, it's like taking a complex idea and breaking it down into smaller, easier-to-grasp pieces, similar to how you would spell out a word letter by letter.