Com*plex"ion (k&obreve;m*pl&ebreve;k"shŭn), n. [F. complexion, fr. L. complexio. See Complex, a.] 1. The state of being complex; complexity. [Obs.]

Though the terms of propositions may be complex, yet . . . it is properly called a simple syllogism, since the complexion does not belong to the syllogistic form of it.
I. Watts.

2. A combination; a complex. [Archaic]

This paragraph is . . . a complexion of sophisms.
Coleridge.

3. The bodily constitution; the temperament; habitude, or natural disposition; character; nature. [Obs.]

If his complexion incline him to melancholy.
Milton.

It is the complexion of them all to leave the dam.
Shak.

4. The color or hue of the skin, esp. of the face.

Tall was her stature, her complexion dark.
Wordsworth.

Between the pale complexion of true love,
And the red glow of scorn and proud disdain.
Shak.

5. The general appearance or aspect; as, the complexion of the sky; the complexion of the news.

• the quality, colour, or appearance of the skin on the face
  
• (figurative) the outward appearance of something
  

• (chemistry) any ion containing more than one atom. e.g. sulphate as opposed to sulphide
  
• (chemistry) any ion in which a central metal atom (normally a transition element) is surrounded by a group of ions or molecules (ligands). e.g. ferricyanide