How popular is “sine qua non” in English? If I use it in day to day conversation, will I be scoffed at?

I saw the word “sine qua non” in the article of New York Times (October 12) written by Gail Collins under the title, “The Gift of Glib.” The article deals with the big Republican debate held in New Hampshire this week, and the word appears in the following sentence:

9-9-9 is the sine qua non of the (Herman) Cain candidacy. It would scrap the tax code and give us 9 percent corporate, income and national sales taxes. He mentions it every 10 seconds (in the debate).

I was able to find the definition of “sine qua non” in Merriam-Webster Dictionary as “something absolutely indispensable or essential” and “Reliability is a sine qua non for success” as a sample of its usage.

I’m interested in how popular or common this word is among native English speakers. I’ve been warned in how-to-write books that abuse of Latin often gives a pedantic tinge and looks odd.

If I use “sine qua non” instead of "essential or basic requirement" in colloquial conversation with native speakers, or even in writing, will I be ridiculed?

If you are trying to communicate clearly, in general it's best to avoid Latin phrases with some exceptions.

First, common Latin abbreviations (etc., e.g., i.e., et al.) are perfectly fine. Similarly, do not hesitate to use Latin phrases that are so common that they are rarely thought of as being a Latin phrase, e.g., status quo, rigor mortis, and per capita.

Also, do not hesitate to use Latin phrases in contexts where they have precise technical meanings. For example, lawyers and academics will use phrases like de facto, de jure, quid pro quo, a posteriori, and a priori with no potential for misunderstanding among professionals.

In summary, if you did not know the meaning of a specific phrase until recently, it may be likely that many other people do not recognize that phrase so its best to avoid it.

In almost every case, the only reason for using any Latin expression it to show how smart you are in knowing it. An English equivalent will usually be more effective.

I use it when it's appropriate, and I think most educated English speakers would. That said, if you use it enough that you feel the need to ask this question, you're probably using it too much.

Using a latin phrase can add an air of emphasis - it in a sense implies that the sine qua non is more essential than the essential element (and of course, both are more important than an essential element).

Well, I am not a native speaker but a 'power user' of the language. I have never heard the Latin phrase being used in a colloquial conversation, or outside of print or a literature classroom. I think it does add a pedantic tinge to the conversation. It will sound heavy and false. A simpler phrase like 'absolutely essential' is more helpful.

I think in certain professions, using Latin terms is common and I have seen "sine qua non" used by educated people without any objection from others.