This is the 9161st most frequent Turkish word.
umur
"Umur" means concern, care, or interest in English.
In this sentence, 'umurumda' is used to express indifference or lack of concern about what is said.
Onun söyledikleri benim umurumda değil.
What he says doesn't matter to me.
Here, 'umursamaz' is derived from 'umur' and denotes the attitude of not caring or being indifferent.
Bu konuda umursamaz davranmak doğru değil.
It's not right to act indifferent about this matter.
In this case, 'umurumda' is used to emphasize caring or concern regarding the lost belongings.