Question

what is the ironic about the story luncheon​

Answer 1

This is dramatic irony. It is based on the strong contrast between what the woman keeps saying and what she actually does. ... Somerset Maugham may have meant the title of his story to be ironic when he called it "The Luncheon," and it turned out to be something of an eating binge.

Answer 2

The story ‘Luncheon’ represents dramatic irony. The woman constantly reminds the other character that he should eat light and that she doesn’t eat much but does the exact opposite of what she supposedly believed.