Is "deficitary" an admissible word?

Solution 1:

If you use a word that is not in common usage, and which cannot be easily found in the most popular dictionaries, then even if it is a real word (perhaps an archaic one), you have to then think about how your audience will receive and understand it. Will they struggle to find a definition and give up? As a native English speaker, I think your audience is more likely to assume a definition, because English speakers 'make up' words all the time - for example, portmanteaus like "fantabulous" - and we recognise them for what they are because there is a degree of familiarity in it. So what would someone likely assume "deficitiary" means?

If a beneficiary is someone who derives or receives benefit from something, then it would seem logical that a deficitary (if such a word exists) would not be someone who is in deficit, but someone who somehow is put into deficit by someone or something else; for example an inherited debt.

As there are other words which suggest a general deficiency or lack, such as "deficient", "bereft", "wanting", I suspect that using "deficitary" would miss what you were trying to say anyway.