御古[ofuru] used article (esp. clothes)
手古摺る[tekozuru] to have much trouble
土耳古[toruko] Turkey
下稽古[shitageiko] rehearsal
懐古[kaiko] recalling the old days

擬古[giko] imitation of classical styles
擬古文[gikobun] classical style
稽古[keiko] practice
遠古登点[wokototen] marks to aid in reading Chinese classics
古え[inishie] antiquity

井泉[seisen] (water) well
黄泉[kousen] underground spring
温泉[onsen] spa
九泉[kyuusen] hades
源泉[gensen] source

古泉学[kosengaku] numismatics
鉱泉[kousen] mineral spring
泉貨紙[senkashi] reclaimed paper
泉水[sensui] fountain