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To begin paying attention and listening carefully (to someone or something). Usually said as a command. Listen up, Joe, this information concerns you as well. OK, listen up, everyone. We only have three hours to complete this project, so let's get to work.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
to listen carefully. (Usually a command.) Now, listen up! This is important. Listen up, you guys!
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
To pay attention closely; be attentive. Used chiefly as a command: Listen up—I'm only going to tell you this once! I want you to listen up and do what I tell you to do.
The American Heritage® Dictionary of Phrasal Verbs. Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
in. to listen carefully. (Usually a command.) Now, listen up! This is important.
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
Pay attention, listen carefully. This slangy imperative probably originated in the armed forces during World War II and soon entered the civilian vocabulary. William Safire used it in a quotation, “I’m only going to say this once, so listen up” (New York Times Magazine, Sept. 28, 1980).
The Dictionary of Clichés by Christine Ammer Copyright © 2013 by Christine Ammer