remarkably; noticeably; by a wide margin
Mimetic adverb describing a sudden, significant change or difference, often in degree, amount, or quality. Commonly used with verbs of change or comparison.
新しいカメラは、前のよりぐんと画質が良くなった。
The new camera has remarkably better image quality than the old one.
彼は練習のおかげでぐんと上達した。
He improved noticeably thanks to practice.
Mimetic word derived from the sound-symbolic element ぐん, suggesting a sudden leap or surge. The exact origin is uncertain.