Loser's Lurgy is an illness, probably not proven to exist, that apparently causes people to perform their activities poorly, i.e. to lose. When Luna Lovegood commentated on a Gryffindor-Hufflepuff Quidditch match in 1996, Luna speculated that Hufflepuff Chaser Zacharias Smith was suffering from Loser's Lurgy because he was performing poorly, to the immense amusement of those listening.
Behind the scenes
- Given that Luna and Xenophilius Lovegood tend to believe in many things that others do not, it is likely that this illness does not exist. This is supported by the fact that the word lurgy is British slang for "a fictitious, yet highly infectious disease", equivalent to the term "cooties". The fictitious disease originated in the The Goon Show episode "Lurgi Strikes Britain."