This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

adj. superlative form of glassy: most glassy.

"In one way, this approach is refreshing: Mr. Norten chose not to present a design that contributes to New York's vertical arms race, in which builders strive to build the highest, sleekest, glassiest buildings possible."