A blank paper that is signed by some authority and given to a person to fill as he or she pleases.
Unlimited discretionary power to act; unrestricted authority.
As an undifferentiated mass, without regard to distinctions; willy-nilly. (Possibly from confusion with another French phrase, en masse.)
A legal document allowing one person to act as the agent of another.
The legal authorisation of one person to act as the agent of another.