じいさん・爺さん・祖父さんjiisan[1]atamadaka (head-high)

1. noungrandfatherusu. 祖父さん; may be used after name as honorific
2. nounmale senior-citizenusu. 爺さん; may be used after name as honorific
   正直しょうじきじいさんは、金持かねもちになった。↗

   The honest old man became rich.

• SynonymおじいさんNeutralThe polite, general word for a grandfather or an elderly man; noticeably more courteous than 「じいさん」.
• SynonymじじCasualColloquial and rough: an old geezer, often contemptuous or self-deprecating, as in 「くそじじい」. Harsher than 「じいさん」.
• Synonym祖父そふNeutralThe ordinary kinship term for a grandfather, yours or anyone's; the usual choice when mentioning your own grandfather to outsiders. Not used as a direct address.
• Synonym翁おきなWrittenWritten and literary: a venerable old man, carrying a respectful nuance, as in 「竹取の翁」. Not conversational.
• SynonymおじいさまFormalAn honorific: respectfully addresses your own or someone else's grandfather, or any elderly man. Formal and polite, unlike the casual 「じいさん」.
• Synonym老翁ろうおうWrittenA written word for an old man, found mostly in literature; never used as an everyday term of address.
• SynonymおじいちゃんCasualWarm, colloquial 'grandpa' — what children typically say. Affectionate and milder than 「じいさん」, which can sound blunt.
• Synonym老夫ろうふWrittenWritten: an old man; also serves as a self-reference by elderly men. Not used in daily conversation.
• Synonym老爺ろうやWrittenWritten and dated: an old man, used sparingly today and never to address someone directly.
• AntonymばあさんNeutralThe counterpart of 「じいさん」: a grandmother or old woman. Like 「じいさん」, it is casual and is also used between spouses.

Use 「じいさん」 to refer casually to an old man or, between spouses, to one's partner. Be politer with 「おじいさん」, affectionate with 「おじいちゃん」, and say 「祖父」 when telling outsiders about your own grandfather; 「おじい様」 adds formality.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 祖父そふのこと。ややくだけた表現ひょうげん。
2. 年としをとった男性だんせいのこと。ややくだけた表現ひょうげん。