旧知
きゅうち · kyuuchi · JLPT N1 · noun
friend
旧 (old) + 知 (known): a person you have known for a long time
旧 — 丨 vertical stroke + 日 sun/day
旧 is the simplified form of 舊, which originally depicted an owl (萑) perched on a nest (臼) and was borrowed phonetically to mean 'old' or 'former.' The modern simplified shape combines 丨 with 日 (sun/day), suggesting days gone by. Today it means 'old,' 'former,' or 'used.'