Brief can be a noun, an adjective, or a verb, and all have different meanings. The noun form is a set of legal documents or a set of specific instructions. The adjective form means to be short in duration or size. The verb form means the act of giving instructions or, especially in military settings, the act of talking about matters in a meeting known as a briefing. It is also used in legal settings outside the United States as the act of instructing a barrister (lawyer) by a brief.
Debrief is the act questioning someone after the completion of a task or project. This review or interrogation is meant to glean information. It was originally used with spies, pilots, or soldiers. It is still used in that setting, but also in general situations for any time one might want to learn from an experience or project.
Both verbs may be conjugated through all the regular forms.
In short, one briefs before a task and debriefs afterward.
Samsung Group executives were briefed Wednesday on the importance of designs and user experiences (UX) to produce goods that meet customer expectations. [The Korea Times]
Navy intelligence officials are frustrated that their chief can’t sit with other services’ intelligence chiefs when they brief Director of National Intelligence James Clapper. [The Washington Post]
On the day I visit, the day before Election Day, one student is sharing a stack of political mail with the other students at his table, three others are preparing for their live election night broadcast, others are debriefing with the teachers about the last-minute push for the campaigns they’ve been working on. [WBEZ]