This is the most critical distinction. `内向 (nèixiàng)` means “introverted” and describes a personality type that gains energy from solitude. An introvert might enjoy a quiet social gathering but feel drained afterward. `社恐`, however, implies fear, anxiety, and avoidance. Someone with `社恐` actively dreads social interaction. While many who identify as `社恐` are also introverts, the terms are not interchangeable.
`害羞 (hàixiū)` means “shy” or “bashful.” Shyness is a feeling of awkwardness or timidity in front of others, especially authority figures or in new situations. `社恐` is a more intense and pervasive feeling of fear and dread about being judged or scrutinized in social settings.
While it stems from a clinical term, using `社恐` in conversation is usually casual. If a friend says, “我社恐,不去了 (Wǒ shè kǒng, bù qùle),” they are most likely just using it as a light-hearted excuse. Don't immediately treat it as a serious cry for help unless the context clearly suggests genuine distress.