(verb)
to eventually agree, acknowledge, or admit that something is valid/true, often hesitantly or grudgingly, after first denying it;
e.g. Eventually, he had to concede that he was responsible for spreading the rumor.
(verb)
to admit or accept defeat in some contest, often hesitantly;
e.g. The captain of the team decided to concede, since there was no way they could win the match.
(verb)
to grant or surrender something such as a privilege, possession, or right, or to yield to a demand;
e.g. He might concede to their demands so he can repair his relationship with them.
(verb)
to allow some advantage to be lost, or to allow someone to gain an advantage (especially in sports, by failing to prevent a point from being scored or a game from being won);
e.g. We cannot concede even one more point, or else our opponents will win the game.