keep your shirt on
Also found in: Acronyms.
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.
keep your shirt onBRITISH, AMERICAN, INFORMAL or
keep your pants onmainly AMERICAN, INFORMAL
If someone tells you to keep your shirt on or keep your pants on, they are telling you to calm down and not be angry or impatient. The doorbell rang. Helen told the caller to keep his shirt on — angry because she felt the ringing had been excessive. Note: This expression is often used to suggest that a person's anger or impatience is not reasonable. Compare with keep your hair on.