異彩[isai] conspicuousness (usu. color)
五彩[gosai] the five colours: green, yellow, red, white and black
光彩[kousai] brilliance
彩り[irodori] coloring
彩る[irodoru] to colour

彩色[saishiki] colouring
彩度[saido] chroma
色彩[shikisai] colour
水彩画[suisaiga] watercolor painting
多彩[tasai] variegated

悪水[akusui] undrinkable water
井戸水[idomizu] well water
一衣帯水[ichiitaisui] (being separated only by a) narrow strip of water
一水[issui] current (of water)
溢水[issui] inundation

飲水量[insuiryou] amount of drinking
飲料水[inryousui] drinking water
烏の行水[karasunogyouzui] quick bath
雲水[unsui] itinerant priest
塩化水素[enkasuiso] hydrogen chloride