Like in Harry Potter 5, Luna Lovegood's father is the author of the Quibbler, a magazine which no one ever takes seriously. "To Quibble" means
1. a slight objection or criticism.
synonyms: criticism, objection, complaint, protest, argument, exception, grumble, grouse, cavil.
2. archaic a play on words; a pun.
1. argue or raise objections about a trivial matter.