Sweat like a pig
Meaning
To perspire very heavily and profusely.
Origin
The common misconception is that pigs sweat a lot, but these animals actually have very few sweat glands and instead wallow in mud to cool down. The true origin of this vivid phrase likely comes from the iron industry of the 18th and 19th centuries. Molten iron was poured into molds arranged in a way that resembled a sow feeding her piglets, hence the term "pig iron." As these newly cast "pigs" of iron cooled, condensation would form on their surface, making them appear to "sweat." This vivid industrial image gave us the enduring phrase, completely unrelated to the actual physiology of the animal.
Examples
- The construction workers were sweating like pigs in the scorching summer sun, despite the early hour.
- After running the marathon, I felt completely drained and was sweating like a pig for hours afterward.