meaning - Is Modificator a word?

Is the word "Modificator" valid - I've never see it before and it's not one I'm familiar with.

Answer

I would say that it is not a valid word.

Collins English Dictionary says:

Sorry, no results for “Modificator” in the Collins English Dictionary.

Oxford English Dictionary says:

No results found for “Modificator”.

The suffix "-ator" is

-ator

used to form agent nouns, usually from verbs that have the ending -ate

And "Modifate" is not a word.

The correct word for what you are looking for is a "Modifier"