oldtimer vs warhorse

oldtimer and warhorse both are nouns.

Word	Noun	Adjective	Verb	Adverb
oldtimer	Yes	No	No	No
warhorse	Yes	No	No	No

As nouns, oldtimer and warhorse are synonyms defined as:

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

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

oldtimer (noun)	warhorse (noun)
an elderly man	horse used in war
an experienced person who has been through many battles; someone who has given long service	a work of art (composition or drama) that is part of the standard repertory but has become hackneyed from much repetition
	an experienced person who has been through many battles; someone who has given long service