Ultimate
noun, の adjective
きゅうきょく
極端 （きょくたん） Extreme
究極 （きゅうきょく） Ultimate
超〜 （ちょう） Ultra, Super, Really
Building the Ultimate 究極 version of something requires research 究 that some might consider extreme 極
The cucumber きゅう cloaking きょく device is his Ultimate invention.
Q きゅう developed the Ultimate cloaking きょく device.