verb [ I or T ] uk / blʌf / us / blʌf / to deceive someone by making them think either that you are going to do something when you really have no intention of doing it, or that you have knowledge that you do not really have, or that you are someone else:

To engage in a false display of confidence or aggression in order to deceive or intimidate someone: The management debated if there would really be a strike or if the union was bluffing.

Bluffing definition, the act of misleading someone by a display of strength, self-confidence, or the like: While the bluffing goes on at the negotiating table, the public, the striking workers, and the employer all lose.