What is 'it' in 'hold it' command?

Question

Why you say 'Hold it.' what means 'Stop.'. What does 'it' means in this command?

Answer 1

Here's an example conversation:

"Then I turned left on Third Street and—"
"Hold it! I thought you couldn't turn left at that intersection?"

In this conversation, the imperative hold it is used to tell the other person to stop talking because there is a point of information that needs to be resolved before the conversation continues.

In this case, it's the turning left at a particular street that is being questioned. However, hold it is being applied to the entire conversation itself.

Hold it is also simply used to signify that the conversation should be stopped. Other expressions include:

Just a minute.
Hang on.
Hold up.
Stop right there.
But, wait.

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Of course, it doesn't need to apply to conversation.

I could walk in on a group of people having a pillow fight and shout "Hold it!" What I'm referring to is the pillow fight itself.

In general, unless using the phrase literally with respect to a physical object you've been asked to hold, it just means that the person you're telling to hold it should stop doing whatever it is that they're doing.

Answer 2

The it in hold it indicates the doing that has to stop because of a certain reason.

It is an informal phrase that means, as you mentioned, wait or stop doing something. Cambridge Dictionary.

Example:

If you were preparing lunch, and suddenly, your father came to the kitchen and opened the fridge. You will understand right away that he wants to snack, so you may say:

Hold it! The food will be ready very soon.

This means, in other words, stop what you are doing, which is opening the fridge to get something to eat, as the food will be on the table shortly.

If you were to say:

Hold! The food will be ready very soon.

Then the question "hold what?" would immediately pop up in our heads since your "phrase" is incomplete.

Stop can also come with it and would mean the same thing as hold it, as mentioned here.

However, in our example, it would be more fit without the it since the phrase "stop it" has an alarming sensation which is really not needed or necessary for the food issue here. So, we would say:

Stop! The food will be ready very soon.

Now, would the question "Stop what?" comes to our minds?

The answer, of course, is no, because stop by itself indicates that you have to put the action you were doing to a pause state, when hold, by itself, doesn't.