from the GNU version of the Collaborative International Dictionary of English
- transitive v. to fight until a decisive and conclusive result is reached.
Sorry, no etymologies found.
I said, "You and Bootroe will have to fight it out now."
The resolution of Grant showed itself in a dispatch written the morning after Upton attacked: "I am now sending back to Belle Plain all my wagons for a fresh supply of provisions and ammunition, and propose to fight it out on this line if it takes all summer."