Literature Reference: 病来城里诸亲故，厚薄亲疎心总知。—— 《病中作》 When illness strikes, in the city, all kin and friends, the depth of closeness or distance, the heart truly knows. Source from 'Bing Zhong Zuo'.
亲:
疎: "Shu", synonymous with "sparse".
Meaning: Qin Shu denotes the closeness or distance in relationships, reflecting the depth or shallowness of emotional bonds.