old-timer vs old stager

old-timer and old stager both are nouns.

Word	Noun	Adjective	Verb	Adverb
old-timer	Yes	No	No	No
old stager	Yes	No	No	No

As nouns, old-timer and old stager are synonyms defined as:

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

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

old-timer (noun)	old stager (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