a must

a must

That which is requisite, necessary, or indispensable. I know this book is a difficult read, but it's an absolute must if you enjoy literature. Taking the introductory course is a must if you want to sign up for the advanced class.
See also: must
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

a must

A necessity; a requirement. For example, The Louvre is a must for visitors to Paris, or This book is a must for serious students of English. [Late 1800s]
See also: must
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

a must

verb
See also: must

must

verb
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
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References in periodicals archive ?
Quick hands and feet are a must. Play on the balls of your feet, not on your heels.
If catching up with your friends is a must, crunch your lunch and chat for part of the time and flip open the books the other part.
A must request from B supplemental information to prepare its Form 1065 properly.
Instead, A must reduce its tax attributes, to the extent of its insolvency, in the following order: NOLs (including carryovers), general business credits, capital loss carryovers, basis reduction of its property and, finally, foreign tax credit carryovers (Sec.
To gain the advantage of solvency, A must demonstrate that the FMV of its assets exceeded the values shown on its balance sheet.