I recently see this word in a Chinese tv drama show. It seems degradative and refers to a man who is deceiving, but what does it exactly mean?
an attractive young man, adonis
gigolo, toy boy
小白脸 is a negative nickname for those who has knowledge or educated. It is from 白面书生. 白面 is saying that this person do not do labor work in the farm and not exposed under sun light, therefore, the face is white.
It is traditionally used by people who can not read and write, but still look down those who can.
Here is a example,
Try this dictionary, I think it is very good.