complexion

temper, character, nature, personality, disposition, complexion

这些名词均有“性格、气质、性情、习性”之意。
temper: 指从感情方面体现出来，决定处理问题或应付形势的方式的性格或性情，这种性情可以是暂时的也可以长久的。
character: 指对个性或人格所作出的客观评价，常常与道德有关。
nature: 指其天性。
personality: 主要指个性。
disposition: 书面用词，指人的主要爱好或思想、精神方面的重要习性、气质。也可指短暂的情绪。
complexion: 指由思维方式、态度和情绪所决定的本质特征。

名词 complexion:

1. the coloring of a person's face
   同义词：skin color, skin colour
2. a combination that results from coupling or interlinking
3. a point of view or general attitude or inclination
4. texture and appearance of the skin of the face
   同义词：skin condition
5. (obsolete) a combination of elements (of dryness and warmth or of the four humors) that was once believed to determine a person's health and temperament

动词 complexion:

1. give a certain color to

1. Her sparkling jewellery served as the perfect foil for her fine complexion.
   她戴著闪闪生辉的首饰，更显得容貌姣好。
2. She has a pale complexion.
   她面色苍白。
3. That colour doesn't suit your complexion.
   那颜色不适合你的肤色。
4. Having white hair and ruddy complexion, my grandfather is hale and hearty.
   我爷爷是位鹤发童颜的矍铄老人。
5. He has a dark complexion.
   他肤色黝黑。
6. This great victory changed the complexion of the war.
   这次大捷使整个战局为之改观。

com.plex.ion

n.（名词）
The natural color, texture, and appearance of the skin, especially of the face.
肤色：自然的颜色、质地和肤色，尤指面部的
General character, aspect, or appearance:
外观：一般的特征、方面或外表：
例句：
findings that will alter the complexion of the problem.
找到改变问题表象的方法

The combination of the four humors of cold, heat, moistness, and dryness in specific proportions, thought in ancient and medieval physiology to control the temperament and the constitution of the body.
体质：古代与中世纪生理学家们认为冷、热、湿、干四种体液的特定比例的组合控制着身体的温度和体质

来源：
Middle English complexioun [physical constitution]
中古英语 complexioun [身体体质]
from Old French complexion
源自 古法语 complexion
from Late Latin complexiô complexiôn- [balance of the humors]
源自 后期拉丁语 complexiô complexiôn- [体液的平衡]
from Latin [combination]
源自 拉丁语 [化合物]
from complexus [past participle of] complecto [to entwine] * see complect
源自 complexus [] complecto的过去分词 [使…缠绕] *参见 complect

【引伸】
complex.ional
adj.（形容词）