* Noun: When referring to people who hold a higher position or rank, "superiors" acts as a noun.
* Example: "He was afraid of his superiors finding out."
* Adjective: In some cases, "superiors" can act as an adjective meaning "of higher rank or quality." This usage is less common.
* Example: "The superior officer was responsible for the operation."
Therefore, the part of speech for "superiors" depends on the specific sentence and its usage.