Stager
Noun
Plural: stagers
Etymology: it is supposed to be derived from the noun stage + -er. Stage is derived from Latin stare (= to stand)
Definition: a person who has long lived, or who has long experience in something, and who, for that, is supposed to be better qualified than a young one; a person praised for his/her long experience in something
Synonym: veteran
Antonyms: experienceless person, beginner, uninitiated
It may be approximately translated by veterano, in Spanish; vétéran, in French; veterano, in Italian.
***It is usually construed with old:
"Ah young men! young men! you're all foolish alike. I don't know how you'd get on, if you hadn't a few old stagers like me to think for you and [… impart] you good advice.
Frank E. Smedley (Frank Fairlegh)
When so old a stager as G. S. does not take the obvious course, the inference is that there is a better course to be taken--not obvious to the uninitiated.
Mary Braddon (Charlotte's Inheritance)
And you are ashamed to confess the truth to me; and you are half ashamed to confess it even to yourself--as if you could deceive an old stager like me!
Mary Braddon (Charlotte's Inheritance)
