御爺さん[ojiisan] grandfather
老爺[shinpu] one's father
狸爺[tanukijijii] cunning old man
好々爺[koukouya] good-natured old man
爺が背[hizaragai] chiton (any marine mollusk of the class Polyplacophora)

エロ爺[erojijii] dirty old man
糞爺[kusojijii] old man
爺さん[jiisan] grandfather (may be used after name as honorific)
洞爺湖サミット[touyakosamitto] G8 Hokkaido Toyako Summit

育ての親[sodatenooya] foster parents
育て親[sodateoya] foster parent
１等親[ittoushin] first-degree relative
仮親[karioya] adopted parents
近親[kinshin] near relative

近親婚[kinshinkon] consanguineous marriage
近親相姦[kinshinsoukan] incest
懇親[konshin] friendship
懇親会[konshinkai] friendly reunion
似非親[eseoya] distant disinterested parent