That's somewhat ironic given how durable the word "cool" has been, despite the general trend of slang to go out of style fairly quickly (c.f. def, bully, radica

That's somewhat ironic given how durable the word "cool" has been, despite the general trend of slang to go out of style fairly quickly (c.f. def, bully, radical, bodacious, groovy, boss, all that, etc...).