血清[kessei] serum
粛清[shukusei] (political) purge
真清水[mashimizu] pure water
清ます[sumasu] to clear
清む[sumu] to clear (e.g. weather)

清い[kiyoi] clear
清まる[kiyomaru] to be purified
清め[kiyome] purification
清める[kiyomeru] to purify
清らか[kiyoraka] clean

適わない[kanawanai] no match for
快適[kaiteki] pleasant
快適さ[kaitekisa] amenity
適う[kanau] to come true (wish)
適える[kanaeru] to grant (request, wish)

好適[kouteki] ideal
最適[saiteki] optimum
最適化[saitekika] optimization
素適[suteki] lovely
適確[tekkaku] precise