To start working on something. Often used as an imperative. Get cracking, or you'll be up all night working on your book report! Let's get cracking—I don't want to spend all day cleaning out the garage.
To leave or depart. Let's get rolling. We need to be at the airport by 7:30. There's nothing happening here—let's get rolling.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
Fig. to get started. Come on. It's time to leave. Let's get rolling! Bill, it's 6:30. Time to get up and get rolling!
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
Begin, get busy, hurry up. The first of these colloquialisms originated in Great Britain in the 1930s and appears to have crossed the Atlantic during World War II. It uses crack in the sense of “move fast,” a usage dating from the late nineteenth century, and is often put as an imperative, as in “Now get cracking before it starts to rain.” The synonymous get rolling, dating from the first half of the 1900s, alludes to setting wheels in motion. It, too, may be used as an imperative, but is more often heard in such locutions as “Jake said it’s time to get rolling on the contracts.”
The Dictionary of Clichés by Christine Ammer Copyright © 2013 by Christine Ammer