To discharge (blood, for example) in the urine.(verb-transitive)
The act or an instance of urinating.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "piss" in a sentence
"Something seemed wrong about saying the word piss in a chapel."
"As a consequence my piss is almost orange in colour at the end of most shifts at the moment!"
"Taking the piss is the hardest thing in the world to explain."