Slang used all the time by Young People
yeya (f) yeyo (m) • adj. • This word basically means “cool” or “nice” It can be used in plenty of contexts
Note: It has a different meaning in other Spanish speaking countries
"Man, te quedo super yeyo el outfit." "Fren, estamos en una fiesta super yeya."
"Man, your outfit is really cool" "Bro, we are at a cool party."
3 out of 9 Spanish, Castilian speakers have heard this