adverb
shaking violently; with a jolt
Mimetic adverb describing a sudden, strong shaking or swaying motion, often of large objects or structures.
地震で家がグラッと揺れた。
The house shook violently in the earthquake.
バスがグラッと揺れて、立っている人が倒れそうになった。
The bus jolted, and the standing passengers nearly fell over.