There are numerous synonyms for the word 'od', which refers to an unpleasant or foul smell. Some of the most common synonyms are stench, reek, fetor, malodor, funk, and pungency. Other related words that can be used to describe an unpleasant smell are stink, whiff, scent, aroma, and fragrance. When describing a strong or overpowering odor, the words effluvium, miasma, and fume can also be used. It is worth noting that the choice of synonym will depend on the context and intended meaning of the sentence. Choosing the appropriate synonym is essential to accurately convey the intended message.