sub·tle
\\ˈsə-t^əl\\ adjective
(sub·tler \\ˈsət-lər, ˈsə-t^əl-ər\\ ; sub·tlest \\ˈsət-ləst, ˈsə-t^əl-əst\\)

 ETYMOLOGY  Middle English sotil, subtile, from Anglo-French, from Latin subtilis, literally, finely textured, from sub- + tela cloth on a loom; akin to Latin texere to weave — more at technical

1.
  a. delicate, elusive
      a subtle fragrance
  b. difficult to understand or perceive : obscure
      subtle differences in sound
2.
  a. perceptive, refined
      a writer's sharp and subtle moral sense
  b. having or marked by keen insight and ability to penetrate deeply and thoroughly
      a subtle scholar
3.
  a. highly skillful : expert
      a subtle craftsman
  b. cunningly made or contrived : ingenious
4. artful, crafty
    a subtle rogue
5. operating insidiously
    subtle poisons
• sub·tle·ness \\ˈsə-t^əl-nəs\\ noun
• sub·tly \\ˈsət-lē, ˈsə-t^əl-(l)ē\\ adverb