i Register
In some senses, guakong is marked as colloquial. Watch for register when choosing this word.
noun
maternal grandfather; maternal grandpa.
term of address for one's maternal grandfather
...they would put together the business, then Francis would marry his fiancée and have children and at last he, Hilario Ong Tian Puy—Ah Puy to his kin and closest friends—would be a true grandfather, not just guakong to his daughters' children...