adverb, adverb taking the 'to' particle
bite or gulp emphatically; chew vigorously
Mimetic adverb describing a forceful, vigorous biting, gulping, or chewing action. Often used with と and verbs like 噛む, 飲む, or 食べる.
犬が大きな骨にがぶりとかみついた。
The dog bit into the big bone with a chomp.
彼はハンバーガーをがぶりと一口で食べた。
He took a big bite of the hamburger and ate it in one gulp.