This is the 626th most frequent Hindi word.
नक
"नक" means "nose" in English.
Here, 'नक' is used to mean 'nose'.
इस चित्र में बाघ की नक बहुत तेज है।
In this picture, the tiger's nose is very sharp.
Here, 'नक-नक' is used in a figurative sense meaning 'detailed inspection'.
संदेह होने पर नक-नक करनी ज़रूरी है।
When in doubt, thorough examination is necessary.
Here, 'नक उतारनी' is a phrase meaning 'to embarrass' implying bringing someone down.