The term 混账 (hùnzhàng) is formed through a metaphorical extension from its original literal meaning in commercial contexts: 混 means "mixed, chaotic, or confused", while 账 refers to "accounts" or "financial records". Historically, it described disordered or fraudulent account-keeping, such as tampering with ledgers to conceal dishonesty. Over time, this concrete idea of "muddling the accounts" evolved into a vivid insult, implying that a person’s character or actions are as morally disordered and shameless as a falsified ledger, hence calling someone "混账" accuses them of being unscrupulous, contemptible, or utterly unreasonable.