Imperceptible(ADJ)
Difficult to perceive by the sense; barely noticeable
Synonyms
Small
Tiny
Unnoticeable
Antonyms
Obvious
Seeable
Noticeable
Sentences
Her dancing was incredibly light; she looked like some exotic poppy swaying to an imperceptible breeze.
Again Barbara gave him that imperceptible and flattering touch.
Imperceptible Electronics (Someya-Sekitani Group, University of Tokyo)