one, etc. in a million

one in a million

Exceptionally uncommon or unusually excellent. Hyphenated if used before a noun. This is a one-in-a-million opportunity for us—we'd be fools not to seize it while we have the chance! My grandmother really was one in a million, and we're all very blessed to have had the opportunity to know her.
See also: million, one
Farlex Dictionary of Idioms.

one, etc. in a ˈmillion

a person or thing that is very unusual or special: My assistant’s one in a million. It’s an opportunity in a million, and we shouldn’t waste it.
See also: million
Farlex Partner Idioms Dictionary
See also:
  • one in a million
  • eleventh hour
  • dooper
  • a round robin
  • round robin
  • wiggy
  • heads I win, tails you lose
  • black market
  • a light touch
  • cop on