What words to express ‘casually’ in Japanese?

気楽きらくに、気軽きがるに、気負きおわずに

何気なにげなく、さりげなく、意識いしきしないで、それとなく

カジュアルな、ラフな、普段着ふだんぎ

短期たんきで、一時的いちじてきに、かる

We can distinguish five meanings of the word ‘casually’ according to the Oxford Learner’s Dictionaries.
Japanese uses different expressions for each meaning.

​1. in a way that shows you are calm and relaxed

the Oxford Learner’s Dictionaries

We can say 気楽きらくに、気軽きがるに、気負きおわずに.

2. without much care or thought; without paying attention to detail

3. showing that you do not want people to know that something is important to you

the Oxford Learner’s Dictionaries

We can say 何気なにげなく、さりげなく、意識いしきしないで、それとなく.

4. if somebody is dressed casually, they are not dressed formally

the Oxford Learner’s Dictionaries

We can say カジュアルな、ラフな、普段着ふだんぎ.

5. not permanently; not regularly

the Oxford Learner’s Dictionaries

We can say 短期たんきで、一時的いちじてきに、かる.


Advanced Tips

I’ll show some example sentences with ‘casually’ meaning of No.1.
Please check the articles of other days for other meanings.

/ I cherish my friends because the time we spend chatting casually with them is more important thing than other things.

わたし友達ともだち大切たいせつにしています。なぜなら、かれらと気兼きがねなくおしゃべりする時間じかんなにより大切たいせつなものだからです。

気兼きがねなくmeans the situation where you can say anything without being worrying too much about each other’s feelings because you know each other so well.

You can say 気楽きらくor 気軽きがる in the same sense in this context.

/ We’ve got older, so the time to stay casually is over.

わたしたちはとしったので、気楽きらくにいられる時間じかんわりました。

In this sentence, 気楽きらく means to be without the responsibility of your family, job or anything like that.

/ He calls out girls so casually.

かれおんな気軽きがるこえをかけます。

In this context, 気軽きがる means to act without thinking deeply.