If someone’s behaviour is described as being beyond the pale, it is deemed unacceptable – they have overstepped the mark of good manners or decency.
A pale was a wooden stake (think of palings) and the word extended its meaning to ‘an enclosed area’ or ‘an area designated to a particular authority’, such as a cathedral pale.
Pales were political areas such as the one in Russia where Jews were allowed to live and the Dublin Pale, enforced under English rule in the fourteenth century as a fortified area safe from the unhappy Irish outside its boundaries.
Civilisation existed within the pale and anything outside this area, or beyond the pale, was seen as occupied by barbarians.
The Native Irish would no doubt have a different story to tell!
The phrase has remained with us. A person behaving inappropriately is not welcome in the inner circle. They, or at least their behaviour, are shunned and doomed to remain beyond the pale.