Uneaten means still there on the plate — food that was served or offered but that nobody ate. It is a plain, factual word with no judgement in it: it does not say the food was bad, only that it was not eaten. Notice how it behaves in a sentence. Almost always it sits right before a noun (uneaten food, an uneaten sandwich, uneaten portions) or comes after the noun in a short tail (she left her dinner uneaten; half the cake went uneaten). That last pattern with go or remain or lie is very common in writing: the letter went unanswered, the food went uneaten, the question remained unasked. English has a whole family of these un- + past participle words meaning 'this thing never happened to it'. Uneaten is used a lot in writing about waste, about hospitals and schools, and about someone who is worried or sad — leaving food uneaten is a classic way for a writer to show that a character has lost their appetite without saying so directly. It is not a word you would often say out loud at your own dinner table; there you would just say 'you didn't eat it'.

沒吃的、沒被吃掉的（食物）。純粹描述事實，不帶「難吃」的意思——只是說東西還在盤子裡。常見說法：剩下沒吃的食物、原封不動的一餐。