Unanimity means that all participants vote for the
motion in question.
It is still the decision-making method used for some sensitive issues in the EU treaties as enlargement with new member states and de cisions on new EU taxes.
The Lisbon Treaty made qualified majority voting in the Council the general rule for EU law making.
Furthermore, it foresees a general passerelle in Article 48.7 TEU: the European Council can move unanimity to QMV in all areas of the TFEU, including CFSP - but except defence, see Art. 48.7.1 TEU.
See also Consensus, Voting in the Council and Treaty changes.