An onomatopoeic adverb expressing a sudden, strong shiver or jolt (from cold, fear, or a sudden vibration).
夜道で物音がして、思わずぶるっと身震いした。
A sound came from the night street and I involuntarily shivered.
冷たい水をかぶって、彼はぶるっと肩をすくめた。
He was splashed with cold water and shrugged his shoulders with a sudden shiver.
古い車のエンジンが急にぶるっと振動した。
The old car's engine suddenly gave a jolting vibration.