blue-sky adjective 1verb 1forms 3 adjective1 •(US, old-fashioned) Involving or relating to fake stocks and bonds.In that connection, when he is heard, I wish you would ask Mr. Commissioner Thompson in regard to his experience with the blue-sky cases; that is, the issuance of fake stock. — 1919 verb1 •To engage in blue-sky thinking about. formsblue-skied · blue-skying · blue-skies
