*pr̥- (Proto-Indo-European)
*bhu- (Proto-Indo-European)
*pro-bhwo- (Proto-Indo-European)
probus (Latin)
(morally) upright, honest, virtuous. Good, serviceable, excellent, superior, able.
probo (Latin)
I acquit, exonerate. I approve, commend. I demonstrate, prove. I test, inspect.