The paradox "monstrous joy" in paragraph 11 of Kate Chopin's "The Story of an Hour" refers to Mrs. Mallard's feeling of elation at news which she knows she ought to regard as tragic. When she is able to analyze her reaction to hearing of her husband's death, she finds that she is overjoyed but understands that there is something monstrous and inhumane in reacting like this.

The paragraph begins with the words:

She did not stop to ask if it were or were not a monstrous joy that held her. A clear and exalted perception enabled her to dismiss the suggestion as trivial.

Mrs. Mallard's emotions are not simple. She recognizes that her husband was (or is) a good man, who has always treated her with love and respect. She feels sorrow at his death, and knows that she will weep for him. Yet she also feels that this sorrow is unimportant when compared with the sense of liberation his absence will confer upon her. Her joy is monstrous, since she is delighted by the death of a good man, but she does not care that it is monstrous because her freedom matters more to her than feeling which she and society both regard as the correct sentiments.