interjection
good morning (to someone late); belated good morning; nice of you to show up
Jocular or sarcastic greeting said to someone who arrives late, often in the morning. A play on おはよう and 遅い.
もう10時だよ。おそよう!
It's already 10 o'clock. Good morning—nice of you to show up!
遅刻した友達に「おそよう」と言った。
I said 'おそよう' to my friend who was late.