piss (something) away
To waste something, especially in a very careless or foolish manner. I can't believe you pissed away our life savings at the racecourse. I had a lot of strings to get you a meeting with the CEO, so don't piss this opportunity away!
piss away
Squander, waste, as in They've pissed away a fortune on those horses. This term uses piss in the sense of "discharge something as though it were urine." [ Vulgar slang; first half of 1900s]
piss away
v. Vulgar Slang To waste or squander something.
piss something away
tv. to waste all of something, such as time or money. (Usually objectionable.) He pissed away the best possible chances.