Casually or inadvertently; doing something without special reason or intention.
何気にテレビをつけたら、昔の友達が出ている番組が流れていた。
I switched on the TV on a whim and an old friend was on a program.
彼は何気に高いことを言ったが、本心かもしれない。
He said something lofty casually, but it might have been sincere.
何気に見たサイトで、欲しかった本が安く売っていた。
By chance I found the book I wanted on a site where it was on sale.
Used to mean unexpectedly or surprisingly — indicating something contrary to expectations.
何気に彼の意見が一番説得力があった。
Surprisingly, his opinion was the most convincing.
その店は何気に料理が美味しくて通っている人が多い。
That shop surprisingly serves tasty food and has many regulars.
Used to express 'after realizing' or 'without noticing' — indicating a realization that came later.
写真を見返していて、何気に髪型が変わっていることに気づいた。
Looking back at the photos, I suddenly noticed that my hairstyle had changed.
彼の言葉を聞いて、何気に自分の考えが変わった。
After hearing him, I unexpectedly changed my thinking.