grand poobah
The most important or powerful person in a group, organization, business, or movement (e.g., the boss, leader, etc.). I think it sounds like a great idea, but you'll have to ask the grand poobah first.
grand slam
1. In the card game bridge, the winning of all thirteen tricks on one deal of the game. I've been playing bridge for years, but I've still never been able to make a grand slam.
2. In baseball, a homerun that is achieved when all three bases have runners on them. It looked like the home team was in for a sure loss, but a grand slam at the last minute edged them ahead of their opponents.
3. (sometimes capitalized) In sports, the winning of all major championships or tournaments in a single year, especially in tennis or golf. The young player shocked the tennis world by winning a Grand Slam in her first year at the professional level.
4. By extension, any total, sweeping victory or success. With the Ohio votes in her favor, it looks like the new president has managed a grand slam.
grand total
The final amount after adding several different numbers or sums. After everything was accounted for, the cost of remodeling the kitchen came to a grand total of $4,500.
grand tour
1. An extended tour or sightseeing trip in, through, or across any country or region. Originally used in specific reference to the major cities of Europe, the trip was considered a necessary part of well-bred gentlemen's upbringing. It was later extended to travel in general. I've been saving up all year long for my grand tour through France.
2. By extension, a comprehensive, guided tour, inspection, or survey. This is your first time seeing our new house, right? Let me give you the grand tour! The general insisted on a grand tour of all the sites that are still operational.
grand scheme
The long term; the complete picture of something. Typically used in the phrase "in the grand scheme of things." I know you're worried about getting a bad grade on this test, but you're such a great student that I doubt it will matter in the grand scheme of things.
busy as a beaver
Also,
busy as a bee. Hardworking, very industrious, as in
With all her activities, Sue is always busy as a bee, or
Bob's busy as a beaver trying to finish painting before it rains. The comparison to beavers dates from the late 1700s, the variant from the late 1300s. Also see
eager beaver;
work like a beaver.
grand slam
A sweeping success or total victory, as in This presentation gave us a grand slam-every buyer placed an order. This term originated in the early 1800s in the card game of whist (forerunner of contract bridge), where it refers to the taking of all thirteen tricks. It later was extended to bridge and various sports, where it has different meanings: in baseball, a home run hit with runners on all the bases, resulting in four runs for the team; in tennis, winning all four national championships in a single calendar year; in golf, winning all four major championships. In the 1990s the term was used for four related proposals presented on a ballot at once.
grand tour
A comprehensive tour, survey, or inspection. For example, They took me on a grand tour of their new house, or The new chairman will want to make a grand tour of all the branches. Starting in the late 1600s this term was used for a tour of the major European cities, considered essential to a well-bred man's education. In the mid-1800s it was extended to more general use.