old-fashioned person; old-timer; old fogey
Refers to a person with outdated values or habits, often used in a mildly critical or teasing way. 昔人間 can sound slightly softer than 古い人間.
My father is an old-fashioned person and won't use a smartphone.
He has an old-fashioned way of thinking.
Compound of 昔 (むかし, 'old times') and 人間 (にんげん, 'human'). The exact origin is uncertain, but it likely emerged as a colloquial way to describe someone whose mindset belongs to the past.