This is the 7404th most frequent Russian word.
господин
"Господин" means "Mister" or "Sir" in English.
Here, господин is used as a formal address analogous to 'Mister' in English.
Добрый вечер, господин Иванов.
Good evening, Mr. Ivanov.
In this sentence, господин is used in a polite and somewhat formal manner to refer to a male person holding a certain position.
Господин директора попросил зайти к нему.
The director asked me to come to him.
Here, господин refers to a gentleman, a term often used in a refined or noble context to describe a male individual.