絕無僅有

绝无仅有
juéwújǐnyǒu
  1. one and only (idiom); rarely seen
  2. unique of its kind

CEDICT

only one of its kind; unique

Wiktionary

極少。

重編國語辭典

Entry Composition

1 絕 jué
  1. to cut short
  2. extinct
  3. to disappear
  4. to vanish
  5. absolutely
  6. by no means
2 無 wú
  1. not to have
  2. no
  3. none
  4. not
  5. to lack
  6. un-
  7. -less
3 僅有 jǐnyǒu to only have; there is only