He tries to keep his private life and public life 'separate' (from each other). = He tries to keep his private life 'separate' from his public life.
('US') He fell and 'separated' [='dislocated'] his shoulder. [=caused the bone in his shoulder to move out of its proper position]
The competition has been easy to this point, but now it gets tough and we'll really begin to 'separate the men from the boys'.
(..) Last year, we had an intern score a . percent on the written exam. He wasn't chosen. It's not a simple pass/fail. It's an evaluation tool we use to separate applicants. Be safe, score a hundred. Okay, let's take a break. Be back in . - Chris, how are you? - I'm good. How you doing? (..)2006 The Pursuit of Happyness