Definition of "imperceptible"

imperceptible

adjective
comparative more imperceptible, superlative most imperceptible
1. not perceptible, not detectable, too small in magnitude to be observed
  Quotations
  A narrow, almost imperceptible path led them through the thickest of the wood. Two or three times they had to creep under boughs which, but for the ease with which they gave way, would seem never to have admitted a passage before.
  1831, L[etitia] E[lizabeth] L[andon], chapter VII, in Romance and Reality. […], volume III, London: Henry Colburn and Richard Bentley, […], page 142
  To my unpractised eye, the undulations in the track were quite imperceptible, but the engineer's hand on the throttle was never still.
  1961 July, J. Geoffrey Todd, “Impressions of railroading in the United States: Part Two”, in Trains Illustrated, page 425
  Very small benefits may be imperceptible. And it is plausible to claim that an 'imperceptible benefit' is not a benefit.
  1986, Derek Parfit, Reasons and Persons, OUP Oxford, page 75
2. beyond the purview of man; too great and all-encompassing to be perceived.