What part of speech is invalid?

"Invalid" can be several parts of speech, depending on how it's used in a sentence:

* Adjective: Describes a noun. Example: "The password you entered is invalid."

* Noun: Refers to a person or thing that is not valid. Example: "The judge declared the contract an invalid."

* Verb: Means to make something not valid. Example: "The court invalidated the agreement."

So, it depends on the context!