big mouth; mouth opened wide
boastful speech; tall talk; bragging; boasting
large amount; large quantity
大口を開けてあくびをした。
I opened my mouth wide and yawned.
子どもが大口を開けて笑っていた。
The child was laughing with their mouth wide open.
熱い食べ物を無理に大口でほおばると危ない。
It's dangerous to force a big mouthful of hot food.