onomatopoeic word for deep sleep/snoring or a rumbling/grumbling sound (e.g., stomach growling).
昨日は疲れて、夜中にぐうぐう眠ってしまった。
I was tired yesterday and slept soundly through the night.
隣の人がぐうぐうと大きないびきをかいている。
The person next to me is snoring loudly.
授業中にお腹がぐうぐう鳴って恥ずかしかった。
My stomach growled during class and I was embarrassed.