noun
Dated term for bubbles or foam, especially from saliva. Modern Japanese more commonly uses 泡 (あわ) or 泡立つ (あわだつ).
赤ちゃんの口元に泡ぶくが浮かんでいた。
Bubbles of saliva were forming at the baby's mouth.
泡ぶくという言葉は今ではあまり使われない。
The word 泡ぶく is not used much nowadays.