A more thorough explanation:

A Bivens action is a type of lawsuit that can be filed against a federal officer who violates someone's constitutional rights while acting in their official capacity. The name comes from a Supreme Court case called Bivens v. Six Unknown Named Agents.

In order to win a Bivens action, the person filing the lawsuit (the plaintiff) must prove that their constitutional rights were violated by the federal officer. For example, if a federal officer conducted an illegal search of someone's home, that person could file a Bivens action for damages.

However, there are some exceptions to Bivens actions. For example, the President of the United States is immune from Bivens actions, and federal officials who are performing adjudicatory functions for an administrative agency are also immune.

Overall, a Bivens action is a way for people to hold federal officers accountable for violating their constitutional rights.