Here's why:
* It describes a noun: We use "friendly" to describe a person, animal, or place. For example: "She's a friendly person." "The dog was very friendly." "It was a friendly neighborhood."
* It can't stand alone as a noun: You can't say, "The friendly walked into the room."
* It doesn't describe an action: It doesn't tell you what someone is doing, unlike a verb.
However, "friendly" can sometimes act as a noun in a specific context:
* Informal slang: You might hear "the friendlies" to refer to friendly people, but this is informal and not standard English.
Examples:
* Adjective: "The dog was friendly towards strangers."
* Noun (Informal): "He's one of the friendlies in the group."