grandad vs gramps

grandad and gramps both are nouns.

Word	Noun	Adjective	Verb	Adverb
grandad	Yes	No	No	No
gramps	Yes	No	No	No

As nouns, grandad and gramps are synonyms defined as:

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

grandad (noun)	gramps (noun)
the father of your father or mother	the father of your father or mother