also: がばと · がはと · かばと · がばりと
suddenly; all of a sudden; quickly; emphatically; energetically
Mimetic adverb describing a sudden, forceful, or energetic action, often with a sense of something happening in a big, sweeping motion. Used with verbs like 起きる, 開ける, 動く, etc.
He suddenly sat up with a jolt.
He flung the door open.
Mimetic word; the exact origin is uncertain, but it likely derives from the sound or impression of a sudden, forceful movement.