old people; being oldคนแก่ means “old person” or “elderly people,” while นี่ adds emphasis and marks the phrase as the topic. The phrase can refer either to elderly people generally or to the experience of being old, depending on context.
TH: คนแก่นี่ต้องดูแลสุขภาพให้มาก
EN: Old people really need to take good care of their health.