The Budapest Gambit is a gambit because black offers a pawn on move two with the idea of gaining rapid development and attacking chances in return. White can either accept the gambit pawn with 3.dxe5 or decline it with 3.Nf3. If white accepts the gambit, black will gain a lead in development and try to use their lead in piece activity to create threats against white's position. If white declines the gambit, black will have a more solid position and will try to use their active pawn structure to gain control of the center of the board.
