old hand vs old stager

old hand and old stager both are nouns.

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

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

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

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

old hand (noun)	old stager (noun)
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