外彊中乾
wài​qiáng​zhōng​gān

tough outside but weak inside

  1. 外 wài locative
    outside
    outside; exterior; the space or position beyond a certain limit or boundary
  2. 彊 qiáng
    opaque (segment carries no independent meaning)
  3. 中 zhōng locative
    middle
    middle; center; within; among; inside a range or period of time
  4. 乾 qián
    [trigram]
    One of the Eight Trigrams (☰) symbolizing heaven and the male principle; one of the Sixty-four Hexagrams (䷀); the compass point 315° (northwest)