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one's father; one's old man; dad; pops
middle-aged (or older) man; old man; geezer
one's boss
proprietor (of a restaurant, store, etc.); landlord
grizzly bear
うちの親爺は頑固だが、根はやさしい人だ。
My old man is stubborn, but at heart he is a kind person.
あの店の親爺は客に対していつも気さくだ。
The owner of that shop is always friendly toward customers.
親爺の背中を見て育ったから、同じ職業を選んだ。
I chose the same profession because I grew up watching my father's back.