～もの・～もん (reason)
Give a casual personal reason
You’ll be able to explain or defend yourself conversationally with a reason that can sound emotional or childlike depending on context.
まだ寝たくないよ。星空がこんなに綺麗なんだもん。
mada netakunai yo. hoshizora ga konna ni kirei na n da mon.
What do you think this sentence means?
I don't want to go to sleep yet! The starry sky is so pretty, after all!
Give a casual personal reason
～もの and ～もん are casual sentence-ending particles used to give a personal reason, excuse, or justification ("because...", "after all..."). ～もん is particularly colloquial, often sounding slightly emotional or defensive.
だって、知らなかったんだもん。
datte, shiranakatta n da mon.
But I didn’t know!
行けなかったの。熱があったんだもの。
ikenakatta no. netsu ga atta n da mono.
I couldn’t go. I had a fever, after all.
Attach もの or もん to plain form
Attach もの or もん to plain forms of verbs, adjectives, or nouns (noun/な-adjective uses なんだもの or なんだもん). It is frequently combined with んだ (んだもの／んだもん).
失敗しても仕方がないよ。まだ子供なんだもの。
shippai shite mo shikata ga nai yo. mada kodomo nan da mono.
It can't be helped if they make a mistake. They are still a child, after all.
「どうしてバスに乗らなかったの？」「だって、すごく混んでいたんだもん。」
“doushite basu ni noranakatta no?” “datte, sugoku konde ita n da mon.”
“Why didn’t you take the bus?” “Because it was really crowded!”
「このシャツ、着たくない。色が変なんだもん。」
“kono shatsu, kitakunai. iro ga hen na n da mon.”
“I don’t want to wear this shirt. The color is weird!”
「駅までタクシーで行ったの？」「ええ、荷物がとても重かったもの。」
“eki made takushii de itta no?” “ee, nimotsu ga totemo omokatta mono.”
“You took a taxi to the station?” “Yes, my bags were really heavy, after all.”
7 more examples in the grammar path — free for a limited time.