complexion (n.) Look up complexion at Dictionary.com
mid-14c., "bodily constitution," from Old French complexion, complession "combination of humors," hence "temperament, character, make-up," from Latin complexionem (nominative complexio) "combination" (in Late Latin, "physical constitution"), from complexus "surrounding, encompassing," past participle of complecti "to encircle, embrace," in transferred use, "to hold fast, master, comprehend," from com "with, together" (see com-) + plectere "to weave, braid, twine, entwine," from PIE *plek-to-, suffixed form of root *plek- "to plait."

Meaning "appearance of the skin of the face" is first recorded mid-15c. In medieval physiology, the color of the face indicated temperament or health.