Carefree with 呑気
呑気 is being carefree or careless. Relaxed and easygoing.
Dictionary Definition
性格や気分がのんびりとしていること。こせこせしないこと。
One's character and mood are in a relaxed manner. Not being anxious.
Goo Dictionary
Examples
Careless until graduation 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:
- 「呑気にしてるとあっという間に卒業だぞ」
- “If you act carelessly, it'll be graduation before you know it.”
The に after 呑気 makes it an adverb.
No time to leisurely eat with 呑気

After an enemy attack changes Usagi and Mamoru into kids, Usagi wakes to find the two of them living together as a couple.
As Usagi wanders into the dining room, Mamoru is placing a plate of french toast on the table. He greets her and asks Usagi what type of jam she wants on her toast.
Usagi responds, then realizes she needs to get to school.
- うさぎ:
- 「あたし ライムのマーマレードッ」
- “I'll have lime marmalade!”
- 「ってそんな呑気に食べてるヒマなんかあたしにはっっ」
- “Ah, I don't have any time to be leisurely eating!”
The に after 呑気 makes it an adverb.