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.
ろうじん
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
日本では、老人の一人ぐらしや二人ぐらしがふえています。
In Japan, more and more elderly people are living alone or in pairs.
あの老人とは仲直りした？
Did you patch things up with that elderly 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.