eccentric
eccentric person
flake *
oddball
geek

The chauffeur merely regarded his master as an eccentric person who was likely to change plans at any time.

But he is in fact as eccentric as a street person.

And did the eccentric person commit any new originality?

Sometimes, eccentric persons become angered because they are hopelessly in debt.

She was an eccentric person who kept a pet blackbird.

She was and always has been a very eccentric and creative person.

And I am quite down-to-earth for such an eccentric person", she insists.

He is known as a somewhat eccentric person.

They knew their master for an eccentric person; but on this occasion, he had shown activity that seemed almost incredible.

A less common origin of the name is as a nickname for an eccentric, or violent person.