"You canker blossom!" 3 Shakespearean Insults
1660s (first attested in Dryden), of uncertain origin, perhaps from pundigron, which is perhaps a humorous alteration of Italian puntiglio "equivocation, trivial objection," diminutive of Latin punctum "point." This is pure speculation. The verb also is attested from 1660s. Related: Punned; punning.
Pun was prob. one of the clipped words, such as cit, mob, nob, snob, which came into fashionable slang at or after the Restoration. [OED]
“And how many hours a day did you do lessons?” said Alice, in a hurry to change the subject.
“Ten hours the first day,” said the Mock Turtle, “nine the next, and so on.”
“What a curious plan!” exclaimed Alice.
“That's the reason they're called lessons,” the Gryphon remarked: “because they lessen from day to day.”