Definition of "haughtiest"

Mademoiselle gave him one of her haughtiest frowns, and turned away. In so doing, the glittering buckle dragged on the ground, and a youth, strikingly handsome, and dressed with just coxcombry enough to indicate that he was not indifferent to the opinion of others, stepped forward, and, dropping on his knee, entreated permission to fasten the buckle. Scarcely looking at him, the Princess accepted his services; the cavalier fastened the clasp, and, bowing profoundly, drew back.

1834, L[etitia] E[lizabeth] L[andon], chapter V, in Francesca Carrara. […], volume II, London: Richard Bentley, […], (successor to Henry Colburn), page 43