oldtimer vs old hand

oldtimer and old hand both are nouns.

Word	Noun	Adjective	Verb	Adverb
oldtimer	Yes	No	No	No
old hand	Yes	No	No	No

As nouns, oldtimer and old hand are synonyms defined as:

oldtimer and old hand: an experienced person who has been through many battles; someone who has given long service

Other synonyms of oldtimer include old-timer, old stager, stager, veteran, warhorse.

oldtimer (noun)	old hand (noun)
an elderly man	an experienced person who has been through many battles; someone who has given long service
an experienced person who has been through many battles; someone who has given long service