This is the 605th most frequent Marathi word.
गमव
To lose.
The word 'गमावलेला' in this sentence indicates something that was lost.
त्याने त्याचा प्रवासासाठी गमावलेला बॅग पुन्हा मिळवली.
He recovered the bag he had lost during his journey.
The word 'गमावला' here is used to denote the action of losing time.
तिने तिच्या कामासाठी वेळ गमावला.
She lost time for her work.
'गमवू नका' demonstrates an avoidance or prevention of the act of losing something valuable.