That would be a trait of character that most inhabitants of a country acquire by education, mimetism or mere abituation, that distinguish them from inhabitants of most other countries; Like a taste for some kind of food or music, a respect (or lack thereof) for some social rules like the patience or reluctance to wait in line, etc. I don't believe this kind of trait can influence economics or politics in any significant measure.

Isn’t that a thing called culture? National character could be another word for it, except “nation” is a modern concept and is highly volatile. Check out what’s happened to the borders of Germany over the last few hundred years.