NEW YORK (AP) -- Groovy is over, hip is square, far out is long gone. Don't worry, though - it's cool. "Cool" remains the gold standard of slang in the 21st century, as reliable as a blue-chip stock, surviving like few expressions ever in our constantly evolving language. It has kept its cool through the centuries - even as its meaning changed drastically. How cool is that? Way cool, say experts who interpret slang for their messages about society. "Cool is certainly a charter member for the slang hall of fame," says Robert Thompson, a Syracuse University professor of popular...