separate the men from the boys—separate those who have great skill, courage, etc., from those whose abilities are more limited:
- The first part of the race is not really difficult; it’s the final three miles over rough and hilly ground that will separate the men from the boys.
separate the sheep from the goats —(also: separate the wheat from the chaff ) separate the good and the bad persons:
- What the government needed was a new leader who would separate the sheep from the goats and show the public that dishonesty would no longer be tolerated.