What does "far out" mean?

Unusual or eccentric; very advanced. for example, Painting blindfolded, that's far out, or Her child-rearing theories are far out.

An interjection meaning “great” or “cool,” as in All he could say when he won the lottery was “Far out!” Originally a slang term for daringly creative jazz, this expression has been applied to other art forms and undertakings. [Colloquial; mid-1900s]