Something that is imperceptible is so small that it is not noticed or cannot be seen.
Brian's hesitation was almost imperceptible.布赖恩的犹豫几乎难以察觉。
The slight change in the taste was imperceptible to most people.这种味道的细微变化对大多数人而言是无法觉察的。She answered with an almost imperceptible nod of the head.她几乎不为人察觉地点了一下头作为回答。His head moved in an almost imperceptible nod.他点头的动作微小得几乎看不出来。The transition is almost imperceptible.这种过渡几乎觉察不到。
1. impossible or difficult to perceive by the mind or senses;
"an imperceptible drop in temperature""an imperceptible nod""color is unperceivable to the touch"