As you know some new words called accidental gaps come into language and obey the phonological rules of the language- they include native phonemes in a permitted order- but have no meaning like BIK or unsad. Some of them currently used as a meaningful word like "argumentation". I looked up such a word in old dictionaries and haven't come across it yet.
Could be "argumentation" term considered as an accidental gap at that time?
Interested in Language