Here's why:
* It describes a noun: We use "lazy" to describe a person, animal, or even a situation. For example: "The lazy cat slept all day" or "The lazy afternoon sun warmed the garden."
However, "lazy" can also be used as a noun in some cases, like:
* A state of being lazy: "He was overcome with lazy contentment."
* A person who is lazy: "The boss was known for hiring lazy employees."
So, while "lazy" is primarily an adjective, context can influence its part of speech.