Meaning:
“社交” means “to socialize,” “自觉” means “self-awareness,” and “症” means “syndrome.” A derivative of the term “社交恐惧症” (shèjiāo kǒngjù zhèng, meaning “social anxiety disorder”), this phrase coined by Chinese netizens refers to those who are self-aware in social interactions and therefore very polite and considerate towards others. For instance, this kind of person will mind their behaviors in public venues, keep their promises, listen to others in conversations and will not ask intrusive questions.
Example:
A: 宿舍里你和谁最合得来？
Sùshè lǐ nǐ hé shuí zuì hédelái？
Who in your dormitory is most compatible with you?
B: 小明。他属于社交自觉症人群，我很喜欢他。
Xiǎomíng。Tā shǔyú shèjiāo zìjué zhèng rénqún，wǒ hěn xǐhuan tā。
Xiao Ming. He is one of those who are polite and considerate. I quite like him.