孤单
gū dān · HSK 7
lonely
😔 孤 = orphan/alone + 单 = single/sole; doubly alone
孤 means orphaned or solitary; 单 means single or one. Stacking two solitude characters yields the feeling of being utterly alone. Note 单 also appears in 单独 (alone) and 简单 (simple).
单 — 叩 (two mouths 口) over 甲 (shield/armor)
Originally a pictograph of a forked hunting weapon or shield with two prongs at the top. The ancient form shows a Y-shaped tool, later stylized into the modern shape. The meaning shifted from the weapon to 'single' or 'one,' possibly because it was a single-handed tool.