Big Brother 
noun
1A person or organization exercising total control over people’s lives: Big Brother will be watching you from this week when spy cameras start to operate in Essex [as modifier]: for executives who want the Big Brother touch, there are monitoring systems to keep track of employees...
- Such is the level of mafia infiltration in society and so dangerous are terrorist attacks everywhere that we are tolerant of these Big Brothers watching their errant siblings.
- Until September 17 of last year, the Canadian government didn't have any Big Brothers on their payroll and we all lived together in blessed harmony within the wonderful realm of free speech.
- There is much speculation about what it is that the Big Brothers from Brussels will say, good and bad, about Bulgaria.
1950s: from the name of the head of state in George Orwell's Nineteen Eighty-Four (1949)
2Australian historical A member of a voluntary organization founded in 1925 which provided foster care for young British immigrants to Australia: he had the honour to be a Big Brother to one of them...
- Well-established Australian citizens would agree to act as a Big Brother to a Little Brother from their homeland.
- They were taken out by Big Brothers, adult members of the Movement, who looked after them.
- The scheme didn't always work out, as Big Brothers sometimes gave inadequate help.