ドタキャン
Dotakyan
どたきゃん
A blend of 土壇場 (dotanba, 'the very last moment') and キャンセル (kyanseru, 'cancel'). It means canceling plans right before they're supposed to happen. In Japan, where reliability and consideration for others are deeply valued, ドタキャン is seen as seriously rude and can damage relationships. The flip side is ドタ参 (dota-san) — showing up to something at the last minute.
Examples
また〇〇にドタキャンされた。3回目だよ
Got dotakyan'd by ○○ again. That's the third time.
Complaining to a friend
体調悪くてドタキャンしちゃった。申し訳ない
I felt sick and had to bail last minute. I feel terrible about it.
Apologizing over LINE after canceling
ドタキャン常習犯とはもう約束しない
I'm done making plans with serial dotakyan offenders.
ドタ参OKって言われたから急遽行くことにした
They said last-minute joiners are welcome, so I decided to go after all.