growl
v. （动物）低沉吼叫，咆哮；（人）低声咆哮着说，恶狠狠地威胁；（事物）发轰隆声；愤愤不平地抱怨
n. 怒吼声，咆哮；（尤指狗发出的）低吠；（机器或引擎发出的）隆隆声
例句
His voice deepened to a growl.
他的声音变成了低沉的怒吼。
《牛津词典》
Their noise modulated to a concerted menacing growl punctuated by sharp yaps.
它们的喧闹声逐渐变为整齐划一的、带有威胁性的吼叫，还夹杂着刺耳的狂吠。
《柯林斯英汉双解大词典》
We hear a louder growl. Guess who is growling?
我们听到了一声更大的咆哮。猜猜是谁在咆哮？
