Idioms and Phrases with all for
Completely in favor of something or someone, as in I'm all for eating before we leave, or The players are all for the new soccer coach. This colloquial phrase was first recorded in 1864.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.