A person who watches or monitors something.

देखरेख करने वाला व्यक्ति

English Usage: The observer noted the behavior of the animals in the wild.

Hindi Usage: देखरेख करने वाले व्यक्ति ने जंगली जानवरों के व्यवहार को देखा।

A person in a position of authority, especially in a military or law enforcement context.

अधिकारी

English Usage: The officer issued a warning to the drivers about the road conditions.

Hindi Usage: अधिकारी ने चालक को सड़क की स्थिति के बारे में चेतावनी दी।