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up and (do something)
To do something quickly, unexpectedly, or abruptly, especially without warning or explanation. I must have offended him, because halfway through the conversation he just up and left. The town has been in a panic searching for a young girl who up and vanished over the weekend. Everyone asks how I came up with the story, thinking it must have taken all this time and planning, but the truth is one day I thought up the premise and then I just up and wrote it.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
Abruptly and unexpectedly: They up and left without saying goodbye.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.