“Nothing will come of nothing”. What does Shakespeare mean by this in the play King Lear?

When Lear stages his silly love test, he asks Cordelia "What can you say to draw a third [of the kingdom] more opulent than your sisters?" Cordelia replies, "Nothing."Lear is offended and says, "Nothing will come of nothing." The idea is that if Cordelia refuses to play his silly game, she will get nothing in the way of inheritance