adjective
Definition: Having no value or importance; insignificant or nonexistent.
Example: The naught of his efforts left him feeling disappointed.
noun
Definition: The state of being nothing or the absence of anything; it can also refer to the number zero.
Example: In mathematics, naught is often used to represent the number zero.
pronoun
Definition: The word refers to nothing or zero; it indicates the absence of anything.
Example: All their efforts were for naught, as the project was canceled.