Glassily
The Century Dictionary and Cyclopedia
In a glassy manner; in such a way as to resemble glass.
the GNU version of the Collaborative International Dictionary of English
adverb.
So as to resemble glass.
Wiktionary, Creative Commons Attribution/Share-Alike License
adverb.
In a
glassy
manner
Word Usage
"Even on the Tunisian side of the border, most Libyans driving in and out smiled glassily, saying that everything inside their country was "good" but offering no details."