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 rosy: most rosy.

"Intelligence officials and diplomats predict that, even under their rosiest scenarios for a more democratic Middle East, the region's emerging governments will be less supportive of U.S. efforts to isolate Iran politically."