What do the terms barbarian and civilized mean? how have their meanings changed over time?

Barbarian: an uncivilised person, especially in Ancient times. Their culture and behaviour was considered offensive of animalistic.

Civilised: culturally and socially advance, refined and an individual that has proper etiquette.

Barbarian, in the ancient times, could apply to warriors, and may have even be considered a positive. Whereas in the 21st century, a Barbarian is considered as a person who acts like an animal and who is crude, giving a negative context.

Civilised people in the olden days may have referred to chivalry eg. holding open doors for women. However, nowadays it may be referred to as being modest, normal classy or refined, the opposite of a barbarian.