Word

HSK	Not in HSK
FREQUENCY	Unknown

潛規則 qián guī zé

unspoken rules (usually ones that codify improper behaviors such as leveraging guanxi to get favorable treatment, or coercing employees for sexual favors)

潛 qián	hide; hidden, secret, latent
規 guī	rules, regulations, customs, law
則 zé	rule, law, regulation; grades