1 general:: Prepare for action, as in I've finished all these memos and cleared the decks for your project, or Clear the decks? here comes the coach. This expression originated in naval warfare, when it described preparing for battle by removing or fastening down all loose objects on the ship's decks. [Second half of 1800s]
American Heritage Idioms
2 general:: Phrase(s): clear the decks 1. Lit. [for everyone] leave the deck of a ship and prepare for action. (A naval expression urging seaman to stow gear and prepare for battle or other action.) • An attack is coming. Clear the decks. 2. Fig. get out of the way; get out of this area. • Clear the decks! Here comes the teacher. • Clear the decks and take your seats.
McGrawhill's American Idioms And Phrasal Verbs