Idioms and Phrases with over and done with
over and done with
Completed, finished, as in That argument's over and done with, so drop the subject. This usage is somewhat redundant but more emphatic than over with. [First half of the 1900s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.