Obsequity as a noun in parallel with obsequiousness

Solution 1:

The use of '[sic]' indicates a known mistake in quoted text. It shouldn't be used in the manner you suggest.

To deliberately invent a word or phrase, you need to call it out in a different manner.

It's possible you could do one of the following, but either might be misunderstood:

It's so-called obsequity.
It's "obsequity."

The first phrasing would sound strange in relation to a word that doesn't exist, while the second could be misunderstood as meaning that you are referring to it in a sarcastic manner rather than one of invention. In both cases, it could be taken as a mistake or typo.

I can see no simple way of getting around this other than to be deliberately informative:

To coin a word, I will call this obsequity.

Here, you are making it clear it's not a typo. By putting it in italics the first time, you're indicating its use as a word. Once you've used it initially, you can use it again later on (in roman type) if you wish.

As a note, Merriam-Webster does have a definition for the noun obsequity:

: the quality or state or being obsequious : obsequiousness

So, a discussion of how to claim it as an invented word may be moot.