The child yowls loudly in the supermarket because his mom won't buy him candy.

yowls 是动词 yowl 的第三人称单数现在时形式。yowl 的意思是"大声哭喊、嚎叫"，通常用来形容孩子或动物发出的尖锐、刺耳的哭闹声。这个词带有负面含义，暗示声音令人不悦或烦躁。