In Chapter 2, Hank uses an idiom, a phrase that has a figurative meaning that's often specific to a certain language or culture, to describe his emotions after he grows frustrated and insults Clarence:
It was pretty severe, but I was nettled.
Nettle refers to a type of plant known for its stinging hairs and the uncomfortable, prickly feeling it induces when touched. Hank is not speaking literally; his use of the phrase "nettled" is an example of an idiom. To be "nettled" means to be annoyed, upset, or irritated by something. When someone is "nettled," it means they are experiencing a sense of annoyance or displeasure, often as the result of someone else's actions or remarks. In having Hank use this phrase, Twain underscores the intensity of Hank's frustration as well as his Yankee roots.
Hank struggles to communicate with the men and women he encounters in King Arthur's Court, which serves as a source of humor as well as drama in the novel. Throughout A Connecticut Yankee in King Arthur's Court, Twain emphasizes just how out of his element Hank is. His use of idiom here is just one example of how Twain highlights the difference between Hank's culture and the medieval one he is forced to navigate and survive in.