This is the 43rd most frequent Hindi word.
इस
"इस" in English means "this" (used for a singular object or person in proximity).
The word 'इस' serves as a demonstrative adjective modifying 'विषय' (topic), specifying which topic is being talked about.
मैं इस विषय पर बात करूंगा।
I will talk about this topic.
Here, 'इस' is a demonstrative pronoun used to indicate the person ('व्यक्ति') being referred to.
क्या आपने इस व्यक्ति को देखा है?
Have you seen this person?
The word 'इस' is used here as a demonstrative pronoun referring to the nearby object 'पुस्तक' (book).