discriminator

noun

1. A person who discriminates, as:

   “keen discriminator”

   “Generally, we may say, that Mr. Smith is a very accomplished etymological scholar, a very keen discriminator, and that his illustrative examples are selected with great industry, and from a wide field of English literature […]”

2. A person who discriminates, as:

   “I am not a discriminator”

3. A test or variable, etc. that serves to distinguish between different things.

   “Colour is not an effective discriminator when it comes to the spiciness of food.”

   “Moreover, the domainness variable also plays the role of weighting discriminators to balance the relatedness of the generated images to different domains. […] Taking semantic segmentation as an example, a typical way is to append a discriminator to the segmentation model, which is used to distinguish the source and target samples.”

4. Any of several electronic devices that convert some property of a signal into an amplitude whose value is proportional to the difference between the value of the input signal and that of a standard.
5. A feature of the seller's offering that differs from a competitor's offering and is important to the buyer in question.

   “An especially strong warranty can be a discriminator in some marketplaces.”