undetectable

• 形容无法被察觉、发现或探测到的。

Describes something that cannot be discovered or noticed.

1. Not easily seenB2formal

   Difficult or impossible to notice with the eyes.

   难以察觉的

   • The stain on the carpet was nearly undetectable.
   • The camouflage made the soldier undetectable in the forest.
   • The tiny crack in the vase was undetectable from a distance.

   同义词concealedhiddenimperceptibleindiscernibleinvisibleobscureunnoticeable

   反义词apparentconspicuousnoticeableobviousvisible

2. Barely able to be perceivedB2formal

   So subtle or faint that it is almost impossible to sense or notice.

   难以察觉的

   • The change in temperature was undetectable to the human touch.
   • His nervousness was undetectable in his calm voice.
   • The difference between the two colors is undetectable to the naked eye.

   同义词faintimperceptibleindistinctobscureslightsubtleunnoticeable

   反义词apparentcleardistinctevidentnoticeableobviousperceptibletangible