Imperceptibleadjective
not perceptible, not detectable, too small in magnitude to be observed
Imperceptibleadjective
Not perceptible; not to be apprehended or cognized by the senses; not discernible by the mind; not easily apprehended.
Imperceptibleadjective
impossible or difficult to perceive by the mind or senses;
Imperceivableadjective
that cannot be perceived; imperceptible
Imperceivableadjective
Imperceptible.