This is the 4079th most frequent Japanese word.
ブッ
"ブッ" is an onomatopoeia in Japanese, often used to mimic the sound of something abrupt, like a puff, burst, or a sudden action.
The word 'ブッ' in this context represents a sudden, forceful action or sound related to laughing.
彼は突然ブッと笑った。
He suddenly laughed loudly.
Here, 'ブッ' conveys the sound of an action occurring abruptly, in this case, the sound of a door shutting.
ドアがブッと閉じた音が聞こえた。
I heard the sound of the door closing with force.
The usage of 'ブッ' here implies a whimsical or sudden expression of complaining or speaking passionately.