Rookie

Etymology

A term for a raw recruit, most likely an alteration of "recruit" itself, in use by the 1890s and popularized by Kipling’s 1892 "Barrack-Room Ballads." Rival theories link it to the chess "rook" or to the "rook," a bird seen as easily duped; the origin is not settled. American sport fixed it as the label for a player’s debut season.

noun · /RUK-ee/
A first-year participant or newcomer, still inexperienced at the top level.
What it names
The status of the talented-but-untested — new enough that mistakes are expected.
Example
A rookie mistake — I replied-all to the entire company.
Related idea
A rookie is new and untested, whereas a veteran is seasoned, carrying the scars and instincts of long experience.