* "sensor" - This is the most common near-homonym. It sounds very similar but has a completely different meaning, referring to a device that detects or measures something.
* "censer" - This is a less common word, but it is a true homonym of "censor" in that it is pronounced the same. It refers to a container used to burn incense.
So, while there isn't a perfect homonym, "sensor" and "censer" are the closest you'll get!