extremely rare; the only one of its kind; (very) unique ❍ 新的一辈继他们的父亲或者母亲之后成为作家的，可以说～，…… (秦牧《两代人》) It is extremely rare for one of the younger generation to follow his father’s or mother’s example and become a writer. …
绝无仅有jué wú jǐn yǒu
比喻非常稀有。unique, the only one of its kind, one and the only one