玻璃心 [bō lí xīn] n. Glass+heart. Glass-like fragile heart. This Internet slang term is used to judge someone who is hypersensitive and emotionally vulnerable. It also alludes to low self-esteem. The term is sometimes used to describe oneself for humorous effect.
When used for criticism, it is similar to “snowflake”—typically describing “millennials who are allegedly too convinced of their own status as special and unique people to be able (or bothered) to handle the normal trials and travails of regular adult life.”