TL;DR: The answer to your query is a person named Chaudhry Sitwell Borisovich who is definitely an entomologist-hymnist and probably is also a mineralogist-ornithologist.

A google search suggests that he was born in 1961.

I ran a few queries using the code and its default dataset, trying to use neutral words for substraction: "mosquito -small +mountaineer", "mosquito -big +mountaineer", "mosquito -loud +mountaineer", "mosquito -normal +mountaineer", "mosquito -usual +mountaineer", "mosquito -air +mountaineer", "mosquito -nothing +mountaineer".

The most frequent words for these queries are:

6 times: "borisovich" "chaudhry" "entomologist" "hymnist" "sitwell"

5 times: "mineralogist" "ornithologist"

Well done, sir.

Well you can dot them if not cross them (cross needs 3 dimensions iirc)!

You inadvertently stumbled onto the punchline of the joke - "You can't cross them because a mountaineer is a scalar." (scaler) - works better when spoken.

Don't forget the part about the mosquito being a vector :)