warhorse vs old hand

warhorse and old hand both are nouns.

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

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

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

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

warhorse (noun)	old hand (noun)
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