How can the word possible be changed to a noun?

You can't directly change "possible" to a noun by simply adding a suffix like "-ity" or "-ness".

Here are some ways to express the idea of "possibility" as a noun:

1. Use the noun "possibility": This is the most straightforward way.

* "There is a possibility that it might rain."

2. Use phrases like "the possibility of...":

* "We are exploring the possibility of expanding our business."

3. Use a related noun:

* "The chance of winning is slim."

* "There is potential for growth in this market."

4. Use a phrase that implies possibility:

* "It's within the realm of possibility that we could solve the problem."

The best option depends on the context and the specific meaning you want to convey.