Is brief an adverb verb adjective or noun?

"Brief" can be several parts of speech, depending on how it's used:

* Adjective: Describing something as short in duration or extent. Example: "He gave a brief speech."

* Noun: A short written or spoken communication. Example: "She sent him a brief."

* Verb: To make something shorter. Example: "I'll brief you on the situation."

It's not an adverb. Adverbs modify verbs, adjectives, or other adverbs, while "brief" usually functions as an adjective or noun.