かっこいい or かっこいい badass or good looking/cool looking
Tabi (traditional workman socks) that of Japan, is really cool looking (badass!)
You can also use カッチョいいー！ or カッケ―！ for extra slangish conversation.
この 音楽 めちゃ かっちょいい！
This music is so badass! ( This music is such a blast!)
Wow definitely badass! (or This is definitely a blast! )