can we get rid of this web dev made up word already?
It should be "compiles".
Granted, there are a lot of situations where there is no need to make a distinction, but that's not always the case.
An analogy might be the use of the words car and taxi. Cars and Taxis are both vehicles. In fact, a taxi is often a car.
In some situations, I might say "I went there by car" - and that would be sufficient. But if the situation demanded I express the fact that the car that I traveled in was a taxi, I would say "I went there by taxi" (Not "I went there by a car that is owned by a freelance driver who charges by the kilometer")
This is why this "word" doesn't make any sense.
However, transcompile simply means source-to-source compiler. A subset of compilers.
Not all compilers take in source and spit out source: They can also output binary information.
So, the shortened "transpiler" doesn't hide that it is a compiler. It just means you get source code out, and put source code in.
And, as sibling commenter noted, "transpilation" is a concept that predates the web itself, let alone "web devs."