a call of nature
call of nature
The urge to urinate or defecate. Jim is off answering the call of nature. Wait a minute, I have to go answer the call of nature.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
a call of ˈnature
(humorous) a need to go to the toilet: He left the meeting to answer a call of nature.Farlex Partner Idioms Dictionary © Farlex 2017