Can the word it be subject of a sentence?

Yes, the word "it" can be the subject of a sentence. It's a pronoun that refers to a previously mentioned noun or idea.

Here are some examples:

* It is raining outside. (Refers to the rain)

* It is a beautiful day. (Refers to the weather)

* It is important to be kind. (Refers to the idea of kindness)

However, it's important to note that "it" can also be used as a placeholder subject in sentences that describe actions or events that don't have a clear noun as the subject.

For example:

* It is getting late.

* It is time to go.

In these cases, "it" doesn't refer to a specific noun, but rather serves as a grammatical placeholder.