Definition of Irony
Early in the novel, Clarissa thinks disdainfully about something Peter Walsh—who loved her and wanted to marry her—said to her a long time ago, before she married Richard Dalloway. As she angrily recalls what he said, the narrative makes use of situational irony to draw attention to the expectations Clarissa used to have for herself and the ways in which she has inadvertently become the very thing she didn't want to become:
How he scolded her! How they argued! She would marry a Prime Minister and stand at the top of a staircase; the perfect hostess he called her (she had cried over it in her bedroom), she had the markings of the perfect hostess, he said.
There's some dramatic irony to the fact that Richard decides to give Clarissa flowers as a way of expressing his love. What he doesn't know is that Clarissa has already bought flowers herself, but readers do know this. In fact, the very first line of the novel announces Clarissa's intention to buy flowers: "Mrs Dalloway said she would buy the flowers herself." As such, the entire time Richard is walking home and proudly thinking about the grand statement he's making by bringing Clarissa flowers, readers know his gesture won't be all that meaningful. In this way, the narrative subtly pokes fun at him as he excitedly prepares to present the flowers to his wife:
Unlock with LitCharts A+But he wanted to come in holding something. Flowers? Yes, flowers, since he did not trust his taste in gold; [...].
Richard brings Clarissa flowers and plans to express his love for her. But when he sees her, he finds himself unable to do so, and Clarissa ends up thinking about how emotionally distant people—including spouses—can be from one another. Richard’s attempt to make a romantic connection with his wife thus only ends up making her feel less connected to him, leading to a perfect example of situational irony. Richard intended to make a gesture that brought him and his wife closer, but the gesture itself ends up making Clarissa feel like there is a "gulf" between them. As he leaves, she thinks:
Unlock with LitCharts A+And there is a dignity in people; a solitude; even between husband and wife a gulf; and that one must respect, thought Clarissa, watching him open the door; [...].
When the Prime Minister arrives at Clarissa Dalloway's party, he's not nearly as impressive as one might expect him to be. Given how much importance everyone seems to imbue him with, it's ironic that he himself doesn't seem very important at all:
Unlock with LitCharts A+One couldn't laugh at him. He looked so ordinary. You might have stood him behind a counter and bought biscuits — poor chap, all rigged up in gold lace.