Noun, English slang: means a person who is being a complete fucking arsehole about Brexit.
Often seen on social media, gloating about 'are country back' to middle ages.
Farage is the mother of all brectums.
Brectum Broadcast Corporation very often broadcasts famous brectums like Farage and Mogg.
Have you seen Farage the arch-brectum on Brexit Broadcast Corporation again? What a gammon. The stupid quitlings believe everything that comes from his brectum.