This is the 4592nd most frequent Polish word.
marnować
"To waste."
marnować is used to express wasting or losing something valuable like time.
Nie powinieneś marnować czasu na rzeczy mało ważne.
You shouldn't waste time on insignificant things.
marnować conveys the idea of wasting, particularly resources or food, implying a negative connotation of not utilizing them suitably.
Po co marnować tyle jedzenia, skoro można je przekazać potrzebującym?
Why waste so much food when it can be given to those in need?
Here, marnowanie refers to the act of neglecting or not utilizing someone's talent or potential effectively.