A Counter-Jinx is a type of spell, that alters the effects of a regular Jinx. Counter-Jinxs vary in light colors, and the wand-movements. When Hermione Granger attended her fifth-year, at Hogwarts School of Witchcraft and Wizardry, Professor Dolores Umbridge told her Defense-Against the Dark Arts class that they had to read a book entitled Defensive Magical Theory as she was supposed to read the first chapter. Hermione read the whole book, and was quized on what Wilbert Slinkard thought on Counter-Jinxs.

Hermione: ".. I've read the whole book."

Dolores Umbridge: "Well then you should be able to tell me what Slinkhard thinks about Counter-Jinxs in Chapter Fifteen.."

Hermione: "He says that counter-jinxes are improperly named. He says "counter-jinx" is just a name people give their jinxes when they want to make them sound more acceptable. But I disagree... Mr. Slinkhard doesn't like jinxes, does he? But I think they can be very useful when they're used defensively..."

Dolores Umbridge: "Oh you do, do you? Well, I'm afraid thats it is Mr. Slinkhards opinion and not yours, that matters within this classroom, Mrs. Granger."