Careless until graduation with 呑気

Vocabulary Explanation: Carefree with 呑気

Aya has mostly given up hope of attracting Shuko’s interest away from their teacher, Mr. Tanaka. Tanaka, having no interest in pursuing a relationship with a student, pushes for Aya to keep trying before the situation changes.

田中(たなか):: 「呑気(のんき)にしてるとあっという間(ま)に卒業(そつぎょう)だぞ」; “If you act carelessly, it'll be graduation before you know it.”

Key Points

1呑気にしてる means acting too carefree

Tanaka warns Aya against being relaxed or careless about the situation.
Here 呑気 has a critical edge: not taking action seriously enough.

2あっという間に means before you know it

Graduation will arrive quickly if he keeps waiting.
The phrase intensifies the warning about lost time.

3〜と sets the consequence

呑気にしてると means “if you keep acting carefree”.
The result is 卒業(そつぎょう)だぞ: it will be graduation.