快復[kaifuku] restoration
快い[kokoroyoi] pleasant
快楽[kairaku] pleasure
快楽主義[kairakushugi] hedonism
快濶[kaikatsu] cheerful

快感[kaikan] pleasant feeling
快挙[kaikyo] brilliant achievement
快哉[kaisai] joy
快作[kaisaku] splendid work
快事[kaiji] pleasure

御新香[oshinko] pickled vegetables
新嘉坡[shingapooru] Singapore
スポーツ新聞[supootsushinbun] sporting newspaper
新西蘭[nyuujiirando] New Zealand
悪徳新聞[akutokushinbun] irresponsible newspaper

維新[ishin] restoration (e.g. Meiji)
一新[isshin] complete change
一新紀元[isshinkigen] new era
改新[kaishin] reformation
革新[kakushin] reform

逸速く[ichihayaku] promptly
音速[onsoku] speed of sound
加速[kasoku] acceleration
加速運動[kasokuundou] accelerated motion
加速度[kasokudo] acceleration

快速[kaisoku] high speed
快速電車[kaisokudensha] high-speed train
角速度[kakusokudo] angular velocity
急速[kyuusoku] rapid (e.g. progress)
減速[gensoku] deceleration