Free man
Karle is a feminine variant of Karl or Charles, derived from the Germanic word 'karlaz'. It traditionally signifies a free person who was not of noble birth but held rights within the community.
Less common today
Karle isn't in the latest US Top 1000. It last peaked at #10,063 in 1995.
US births per 5-year period, 1990βpresent (SSA data).