surreptitiously
🇺🇸
/ˌsɜːrəpˈtɪʃəsli/
🇬🇧
/ˌsʌrəpˈtɪʃəsli/
adverb
R
in a way that is meant to be hidden or not easily seen
The spy took the document and left the room surreptitiously.
スパイは秘密裏に文書を受け取り、部屋を後にしました。
translation
こっそり