Brexit is the UK’s withdrawal from the European Union
The word Brexit is made out of British and exit. Following a referendum held on 23 June 2016 in which 52% of votes cast were in favour of leaving the EU, the UK government intends to invoke Article 50 of the Treaty on European Union, the formal procedure for withdrawing, by the end of March 2017. This would put the UK on a course to leave the EU by March 2019.
Prime Minister Theresa May, elected by the ruling Conservative Party in the wake of the referendum, has promised a bill to repeal the European Communities Act 1972 and to incorporate existing EU laws into UK domestic law. The terms of withdrawal have not yet been negotiated; in the meantime, the UK remains a full member of the European Union.
Source: Wikipedia