imperceptible

Definitions

Impossible or difficult to perceive by the mind or senses.

So slight, gradual, or subtle as to be barely noticeable.

Examples

The change in the room's temperature was so imperceptible that no one noticed the heater had turned off.

She felt an almost imperceptible tremor in his hand as he reached for the glass.

There was an imperceptible shift in his expression, suggesting he was hiding his true feelings.

Synonyms

unnoticeable indiscernible faint subtle invisible slight inconspicuous

Antonyms

noticeable obvious perceptible evident apparent distinct conspicuous