imperceptible
/ˌɪmpəˈsɛptɪbəl/adjective
Too slight or small to be noticed or sensed.
Example sentences
- “The change in temperature was so gradual it was imperceptible.”
- “The scratch on the screen is imperceptible unless you hold it up to the light.”
Often softened with 'almost' or 'nearly': 'an almost imperceptible nod'.