The act of going behind a man (random or acquaintence) and jiggling his balls. This could be sneaky, out in the open, or an act of retaliation. No homo.
Man 1: What happened? Why do you look so surprised?
Man 2: Ho-Holy shit! Diaz just grindel swapped me!
Man 1: Oh.
The first Dark Lord within memory in the Potter-verse. Described in the book as having golden curls and being quite good-looking, and was apparently young Albus Dumbledore's best friend with whom he plotted Muggle domination. Stole the Elder Wand (see HP 7: The Deathly Hallows), the least of the Deathly Hallows. Defeated by the same Albus Dumbledore that was his best friend.
A type of Grindle that snaps. If you get close you have the threat of getting snapped. This can cause some Laceration in the body or sternum that can cause death.
Jennifer: Watch out! There's Grindlesnappers over there! You can die if you get too close!