unobserved
adjective uk/ˌʌn.əbˈzɜːvd/ us/ˌʌn.əbˈzɝːvd/
不被人看到的;没有注意到的;被漠视的
without anyone watching or noticing
So tiny that they often go unobserved, biting gnats can be only 0.5 mm long. 小黑蚊非常之小，人们常常都注意不到，有的只有0.5毫米长。
- More examples
- Never leave a child unobserved around water, including bathtubs and 5-gallon buckets.
- I managed to get down the stairs unobserved.
- Since rape is likely to be an unobserved crime, victims may not have corroborative evidence.
- Many beautiful and moonless nights have passed unobserved because I was too exhausted to carry a hundred pounds of equipment into the backyard.