British definition of Snicker. It means to chuckle or giggle.
รขยยI had a dream about a motorcycle," said Harry, remembering suddenly. "It was flying."
Uncle Vernon nearly crashed into the car in front. He turned right around in his seat and yelled at Harry, his face like a gigantic beet with a mustache: "MOTORCYCLES DON'T FLY!"
Dudley and Piers sniggered.
"I know they don't," said Harry. "It was only a dream.รขยย
Was from Harry Potter and the Philosopher's/Sorcerer's Stone.