In software design, we can say a class is a polymorphic class. If a class is not a polymorphic class and I want to make it one, do I say I've polymorphized the class?
Polymorph is a word software folks created from the some handy Greek-ish roots poly (meaning "many") and morph (meaning "change"). The idea is to indicate that the base type (aka: class) in question can be easily changed in many possible ways (generally via a derived class of some kind). It is generally used as an adjective (it modifies a noun) or an adverb (modifying a verb like is).
So back to English grammar. Often we can transform a noun to a verb with an "ize" on the end to indicate that we have somehow transformed the subject of the sentence into that other noun. For example, if I transform an array into a raster, you could say I rasterized the array.
However, its kind of awkward to do this with an adjective or adverb rather than a noun. I'm sure its done from time to time, but not ubiquitously. For example, if I paint something blue, you wouldn't likely hear someone say that I blueized that thing.
Now you could try to transform your noun into a verb just by adding a simple -ed on the end (polymorphed). However, as I think you suspected, that would be saying that you actually changed the subject itself, which isn't the point of what you want to say at all.
So I don't think you can get around the somewhat wordy, "made it polymorphic".
I've never needed to use the term. However, I might say:
I've refactored the class to become polymorphic.
You can if you want to.
It’s not in common usage yet. A phrasing like “…made
So: if you like it, go for it!