Punning and groaning are brothers.

The line wittily links two familiar reactions to wordplay: the speaker’s delight in a pun and the listener’s “groan” at its corny cleverness. By calling them “brothers,” it suggests they are inseparable—puns almost naturally generate groans, and groans are part of the social ritual that makes punning work. The phrasing also hints at a kinship between humor and discomfort: a pun’s pleasure often comes from forcing language into an awkward fit, and the groan marks that strain. Overall, the quote treats punning as a communal, performative act where approval and mock-disapproval coexist.