(of a pig) to make a low, rough noise

The pigs were grunting contentedly as they ate their food. 猪边吃边发出满意的哼哼声。

(of a person) to make a short, low sound instead of speaking, usually because of anger or pain

He hauled himself over the wall, grunting with the effort. 他费力地翻过墙，累得直哼哼。

[ + speech ] "Too tired," he grunted and sat down. “累死了，”他呻吟着坐下来。