pie-in-the-sky

From the noun pie in the sky.

• (Received Pronunciation, General American) IPA^(key): /ˈpaɪ n̩ ðə ˈskaɪ/

• Audio (AU)

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• Rhymes: -aɪ

pie-in-the-sky (not comparable)

1. (idiomatic) Lacking reality and serviceability.

   a pie-in-the-sky patent

2. (idiomatic) Of a dream unlikely to ever come true; impractical, unrealizable.
   • 2017 March 1, Anthony Zurcher, “Trump addresses Congress: A kinder, gentler president”, in BBC News‎, archived from the original on 5 June 2017:

     If his [Donald Trump's] detailing was productive, it was somewhat undermined by a final, typical Trumpian flourish of pie-in-the-sky rhetoric.