じいちゃんじゃなかったです
爺ちゃんじゃなかったです
jiichanjanakattadesu

Noun
Desu Copula

The polite, past negative form of じいちゃん

1. It wasn't Grandpa.; It wasn't old man.

Past/Perfective
Negative
Polite
Casual Register
Usually Written in Kana