内行
nèi háng · HSK 7
expert
🎓 内 inside + 行 (háng) the trade = someone inside the trade = an expert
Here 行 is read háng meaning a trade or profession, not xíng. An 内行 person stands inside the trade rather than outside it, so they know it from the inside out. The opposite is 外行 (wài háng), an outsider or layperson.
内 — enclosure 冂 + enter 入
内 originally depicted something entering (入) into an enclosed space (冂), giving the core sense of 'inside' or 'within'. The pictographic image of going into a covered area extended naturally to meanings like inner, internal, and inland. It contrasts with 外 ('outside').
行 — crossroads pictograph (left 彳 + right 亍)
行 originally pictured a four-way crossroads in oracle bone script, with two paths meeting. From 'road' it extended to 'walk, go, travel,' and then to 'a row, line' or 'business firm' (read háng). The two halves 彳 and 亍 are the split sides of that ancient crossroads.