当孤独已成习惯
[dāng gū dú yĭ chéng xí guàn]
The name means 'When Loneliness Becomes Habitual'. It expresses that the person may have been alone for a long time and got accustomed to solitude. This user name could reflect an attitude of acceptance toward their situation, or maybe even an enjoyment of solitude instead of fearing loneliness.