imperceptibly
🇺🇸
/ˌɪmpərˈseptəbli/
🇬🇧
/ˌɪmpəˈseptəbli/
so slightly or gradually that it is not noticeable
The temperature dropped imperceptibly throughout the day.
온도는 하루 종일 미미하게 떨어졌습니다.