Dishonesty... I'm not sure you are using that word correctly. It does not mean "disagrees with me".
Many people would argue that as far as economics is concerned, "supply" is shorthand for "apparent supply", which is more or less the same thing as saying "in circulation".
But this is exactly what the definitions are not being used for. They are being used to refer explicitly to increases or decreases in the quantity of money--notions that are completely irrelevant compared to the effects of money in circulation which has many more complex interactions and implications. These "easy" definitions are being used to pretend that the problems associated with deflation are not worth talking about because, lol, there is no deflation.
Your PS is silly. People use "inflation" to mean either "increase in quantity of money" or "increase of prices". The inverse terms are "deflation", "decrease in quantity of money" and "decrease of prices". If we have offended you by failing to use one of those terms sufficiently, we apologize for the oversight.
You pointed out that inflation was originally a term used to describe an increase of money in circulation. It is now used to describe a general increase in the price level. Historically, deflation as a term came about much later than inflation and always referred to a general decrease in the price level. No one of any merit has ever used it to mean specifically a decrease in the quantity of money or money in circulation. At some point, you have to give up this silly definition charade because all it does is create a microcosm of bitcoinomics that hinders any real discussion--likely the intended purpose. Intellectual dishonesty.