What is another word for niff?
Pronunciation: [nˈɪf] (IPA) 
The word niff is a slang term that is commonly used in British English to describe an unpleasant odor. However, there are other synonyms that could also be used to describe this particular aroma. For instance, stink, whiff, reek, odor, miasma, and smell are all perfect synonyms that could be used in place of the word niff. These words are all vivid, descriptive, and would definitely capture the intended meaning of the term niff. So, whenever you come across a foul scent, you can always use any of these words to express it.
