Yes, "ready" can be an adjective.
Here's why:
* Describing a noun: "The food is ready." (Describing the state of the food)
* Modifying another adjective: "He's perfectly ready for the test." (Modifying the adjective "perfectly")
However, "ready" can also be a verb.
For example:
* "Ready yourself for a long journey."
So, to determine if "ready" is an adjective, you need to look at how it's used in a sentence.