This word is a lexical morceau that, it turns out, is not to everyone’s taste. There are some who believe that it should be – must only ever be – two words, and that moreso is like a miscegenation from the Island of Dr. Moreau. They are prone to making martial morsures into those who leave out that little space. They are peeved like those incensed by incent, or even moreso.
As witness I present a tweet I saw last fall, twotten by someone I will leave unidentified so as not to seem personal about it:
It seems like one would have to have read very little over a lifetime to think that “more so” was one word…
It occurs to me that the more one reads, the more likely one is to encounter variant forms. And since English speakers will often infer that odd variants we see must be correct (unless someone tells us otherwise), I believe that a person who thinks there is a word moreso may well have read quite a bit.
It is true, certainly, that more so exists much more commonly as two words, and that the one-word moreso style seems to have appeared mainly in the US and mainly in the last century or less. Nonetheless, it is used, and sometimes by quite literate people in respected publications; moreover, it can be found in the Oxford English Dictionary (as a “chiefly U.S.” variant of more so), though not all other dictionaries include it.
Now, insofar as it is just more so without a space, is there a case to be made for it at all? We can see why a person may incline to make it one word: we have words such as moreover and insofar, so it wouldn’t be the first agglutination of that sort; also, there is a particular pattern match with also (the al being the same as in words such as already and alright); and this parallelist tendency is abetted by the fact that the so is unstressed.
Now, with already and alright, we can see that all ready and all right can exist as forms with double stress and a different sense. Can more so exist with double stress and a different sense? I can imagine an uncommon instance where so is being used in conjunction with an indicating gesture – “Do you like my hair more so, or more so?” For the most part, though, it is a compound said always with one stress – like how North Americans say ice cream, only moreso.
A compound! Yes, more so is really an open compound, and moreso is the same compound just closed up. It would thus seem like the natural end condition for more so to merge into moreso. Mind you, we still don’t write icecream – well, most of us don’t, anyway. But compounds do close up in many cases. What keeps them from closing up? Tradition… and clarity.
And clarity may yet come into play here. As another Twitterer (who I will also not name, in this case just to be consistent) twet:
Whenever I see someone spell “more so” as one word, I assume it’s Spanish and pronounce it mo-RAY-so.
Indeed, the biggest obstacle to the ultimate supervenience of moreso may be not traditionalists (obstacles though they can be) but English spelling. It runs into the same kind of problem as coworker, which can look distractingly like it should be “cow orker.” Mind you, I would not say that moreso has the problem quite as much so – it is like coworker, yes, but surely less so. Still, combine that with tradition and the lack of other matching forms in its particular set (asmuchso, lessso) and it will be worth watching to see whether moreso can prevail.