blue-sky

[bloo-skahy]

adjective

fanciful; impractical: blue-sky ideas.
(especially of securities) having dubious value; not financially sound: a blue-sky stock.

Origin of blue-sky

First recorded in 1890–95
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019


British Dictionary definitions for blue sky

blue-sky

blue-skies

noun

(modifier) of or denoting theoretical research without regard to any future application of its resulta blue-sky project

verb -skies, -skying or -skied

to theorize (about something that may not lead to any practical application)
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012