keep shirt on

keep (one's) shirt on

To remain calm and wait for something. Typically used as an imperative in the phrase "keep your shirt on." Keep your shirt on, dude, the pizza will be here soon enough. It would have gone smoothly if Larry had been able to keep his shirt on instead of trying to get in early.
See also: keep, on, shirt
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

keep one's shirt on

 and keep one's pants on
Fig. to be patient. Wait a minute! Keep your shirt on! Keep your pants on! I'll be with you in a minute.
See also: keep, on, shirt
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.

keep (one's) shirt on

Slang
To remain calm or patient: The plane doesn't land for another hour, so keep your shirt on.
See also: keep, on, shirt
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.
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