Any appropriately cleared individual with a requirement to access an information system (IS) for performing or assisting in a lawful and authorized government function.
Sources:
CNSSI 4009-2015
from
DoDD 8570.01 - Adapted
Any appropriately provisioned individual with a requirement to access an information system.
Sources:
NIST SP 1800-27B
under Authorized User
from
CNSSI 4009-2015