breaking into a cold sweat from embarrassment or fear
A yojijukugo describing a state of extreme embarrassment or fear that causes one to break out in a cold sweat. Often used in literary or emphatic contexts.
I messed up in front of a large crowd and felt like I was breaking into a cold sweat.
冷や汗 is the common word for 'cold sweat' and can be used in everyday situations. 冷汗三斗 is a more dramatic, literary yojijukugo emphasizing the intensity of the sweat.
The expression 冷汗三斗 literally means 'cold sweat three to (a unit of volume)', suggesting a large amount of cold sweat. The exact historical origin is uncertain, but it is a fixed yojijukugo used to emphasize extreme embarrassment or fear.