granddaddy vs granddad

granddaddy and granddad both are nouns.

Word	Noun	Adjective	Verb	Adverb
granddaddy	Yes	No	No	No
granddad	Yes	No	No	No

As nouns, granddaddy and granddad are synonyms defined as:

Other synonyms of granddaddy include gramps, grandad, grandfather, grandpa.

granddaddy (noun)	granddad (noun)
the father of your father or mother	the father of your father or mother