Wiktionary
n. (context politics English) A member of a government having the rank of cabinet minister, but not assigned to oversee a particular government department or other permanent area of responsibility.
Wikipedia
A minister without portfolio is either a government minister with no specific responsibilities or a minister who does not head a particular ministry. The sinecure is particularly common in countries ruled by coalition governments and a cabinet with decision-making authority wherein a minister without portfolio, while he or she may not head any particular office or ministry, still receives a ministerial salary and has the right to cast a vote in cabinet decisions. In some countries where the executive branch is not composed of a coalition of parties and, more often, in countries with purely presidential systems of government, such as the United States, the position (or an equivalent position) of minister without portfolio is uncommon.
Minister without portfolio is a minister in the Government of Serbia with no specific responsibilities or a minister that does not head a particular ministry.
The office was usually held simultaneously by several people at the same time (in the government of Mirko Marjanović there were ten Ministers without portfolio at one point).
The current Ministers without portfolio are Jadranka Joksimović (since 27 April 2014), Slavica Đukić Dejanović and Milan Krkobabić (since 11 August 2016).
Usage examples of "minister without portfolio".
The Premier of the People's Republic was a man known for his detachment, but he'd always regarded his Minister Without Portfolio with a certain degree of warmth.
The best chief of ONI in two centuries, and currently a cabinet minister without portfolio.
He has his own letterhead and email identity, a sort of minister without portfolio, with no bureaucracy to command and no money to disburse.
He was back at the Martini Terrace within three-quarters of an hour of leaving, and in time to hear Agnes tell a drunken minister without portfolio to peess off.
He had been Minister without Portfolio, you may remember, when Bonforte was Supreme Minister, but that says nothing.