single word requests - what do you call a civilized person?

In colloquial AmE there is the admonition, "Why don't you act like a human being?" which implies civilized behavior - or the shorter, "C'mon, be human" which means the same thing.

In the NE US, we often say "He/She is 'good people'" (using the plural for a single person) to mean someone who is thoughtful, friendly, down-to-earth, and/or generous. We also borrow the Yiddish expression mensch (literally, 'person') but used in the same way.