vi.

1. 抱怨，發牢騷[（+at/about/over）]
   But there is no use in grumbling.

   可抱怨有什麼用呢。

2. 咕噥；發哼聲；發轟隆聲

vt.

1. 埋怨；對……表示不滿[（+out）]
   He grumbled out his reasons for refusing the command.

   他生氣地說出拒絕執行該項命令的理由。

n.

1. 怨言，牢騷[C]
   She is full of grumbles.

   她牢騷滿腹。

2. 轟隆聲[the S]

v.

1. complain in a bad-tempered way.
2. make a low rumbling sound.
3. [usu. as adj. grumbling] (of an internal organ) give intermittent discomfort.

n.

1. a complaint.
2. a grumbling sound.