Adjective subtle has 4 senses
  1. elusive, subtle - be difficult to detect or grasp by the mind; "his whole attitude had undergone a subtle change"; "a subtle difference"; "that elusive thing the soul"
    Antonyms: palpable, tangible (indirect, via impalpable)
  2. subtle - faint and difficult to analyze; "subtle aromas"
    rugged (indirect, via delicate)
  3. subtle - able to make fine distinctions; "a subtle mind"
    unperceptive, unperceiving (indirect, via perceptive)
  4. insidious, pernicious, subtle - working or spreading in a hidden and usually injurious way; "glaucoma is an insidious disease"; "a subtle poison"
    Antonym: harmless (indirect, via harmful)