purple squirrel
noun
a hypothetical person sought by an employer, with the ideal combination of temperament, experience, and education for a particular job.
The grammatical form denoting more than one person, place, thing, or idea.
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
A Talbot of Lancashire had three purple squirrels in a silver shield.
From Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 3 "Helmont, Jean" to "Hernosand" by Various