No. The Oxford English Dictionary (OED) and Oxford Learner’s Dictionaries only list standard spellings. The correct spelling is "sexy" (one 'x', one 'y'). The stretched version is internet slang for emphasis, not a real word.
To help you accurately, here’s a clear, informative post about the actual phrase — including dictionary meaning, usage, and how to find reliable translations online for free. here’s a clear
The full OED requires a subscription, but you can: here’s a clear
as a phrase means "sexually attractive women." It is not a fixed idiom but a common adjective-noun combination. here’s a clear
Internet culture often distorts spelling to match how a word might be shouted or whispered in a playful or provocative way. 4. Why Use an "Online Free" Dictionary?