Old Person
Elderly Person
noun, の adjective
An elderly person is an old person (or an elderly person). Don't call a person a 古い人, though. 古い is used for things, not people. Be nice, they're your elders.
This is a jukugo word, which usually means on'yomi readings from the kanji. Since 人 has two on'yomi readings, here's a mnemonic to help you remember which one to use:
Every old person has roe jeans(ろうじん), a special pair of jeans smeared with roe that they wear when they go out on the town. Some elderly people have cod roe jeans, some have salmon roe jeans… But tofugu roe jeans (adorned with the roe of the lesser spotted tofugu) are the most fashionable of all.
老人クラブ
senior citizens' club
老人人口
elderly population
老人ホーム
nursing home
日本は老人の人口がとても多いんですよ。
Japan has a very large population of elderly people.
生まれたばかりの赤ちゃんだって、いずれは老人になります。
Even a newborn baby will eventually become an old person.
うわ！あの老人めちゃくちゃイケメンでマッチョなんだけど。
Wow! That old man is such a hunky beefcake.