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.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
keep one's shirt onand 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.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.
keep (one's) shirt onSlang
To remain calm or patient: The plane doesn't land for another hour, so keep your shirt on.
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.