pronoun
he; she; that person
A polite or slightly distant way to refer to a third person. Can also be used by a speaker to refer to their spouse or partner, often with affectionate or humble nuance.
あの人は私の父です。
That person is my father.
うちのあの人、今日は遅くなるって。
My husband (lit. that person of ours) said he'll be late today.
pronoun
Archaic second-person usage, now obsolete. In modern Japanese, あなた or other terms are used instead.
古文では「あの人」が「あなた」の意味で使われることがある。
In classical texts, あの人 can be used to mean 'you'.
More direct and informal 'he'; あの人 is politer and can refer to either gender.
Specifically 'she'; あの人 is gender-neutral and more distant.
'This person' (closer to the speaker); あの人 refers to someone farther away or not present.
Compound of あの (that) + 人 (person). The second-person sense is an archaic extension.