I have a hard time understanding you precisely, as you seem to say different things at different times.
Let me focus on this:
The word tarocco or tarocho is pronounced Tarok in French. The word Taroch pronounced Taró in French, what Tarau is written. Similarly, the word Moulinaux is pronounced mulin (without final consonant) while Pique is pronounced (the final consonant is pronounced because it is followed by vowel).
The word "tarocco" or "tarocho" does not exist in French. It exists in Italian. If there were a word in French pronounced "tarok" it would be spelled "taroc", as French typically does pronounce "c" at the end of words (e.g, "avec"); the 1879 dictionary does have that word with that spelling, "taroc," as a Provençal word for "tarot", the game.
Then you speak of a word "Taroch" pronounced "Taró" in French, written "Tarau". Again, it is not at all clear that a word "Taroch" would be pronounced "Taró" in French. You give as an example "Moulinaux", pronounced without the final consonant "x". Yes, that is correct for "x" in that case and most others (exception: dix): Moulinaux" is pronounced "Moulino". But that is not true for final "ch".
There are different ways in which final "ch" is pronounced in French: as "k", as "sh" and, if "tch", then either like "tsh" or "tch" in English. In general, final "ch" in French occurs in words taken from other languages, and its pronunciation varies according to the original. But it is not dropped. For example, there is the French word "trach", which comes from German: the "ch" is pronounced as "k" (
https://en.wiktionary.org/wiki/krach). There is also the word "bortsch", from Russian or Ukrainian: here it is pronounced as "sh" (
https://www.cnrtl.fr/definition/borsch/ .
Anyway, we are dealing with not only "ch" but also "-cco", and in general the "k" sound, either at the end or with an "o" added. In Italian, there is the word "Morocco", a country in north Africa; in French it is "Moroc". The "c" is pronounced as "k":
https://en.bab.la/pronunciation/french/maroc. There is also the Italian word "marocchino", meaning goat-skin leather; it goes into French as "maroquin". Again the "k" sound remains, although the "o" ending is dropped.
It is true that sometimes "c" is silent at the end of a word in French. "Tabac" in French has silent "c". But this does not seem to be a word derived from Italian (where it is spelled "tobacco"), but rather from the Spanish, "tabaco", or else directly from New World, perhaps Haiti, in either case with the "o" present, "tabago". Nor is it a word ending in -occo.
Then there is "tarochus". In general, Latin words ending in "-us" end in "o" in Italian, and vice versa. I suspect that "tarochus" is a made up word from "tarocho". In that case, "tarocho" would precede "tarochus" in time. I see no reason to insist that the word did not exist before 1495. It can take time before a word gets used in writing that is preserved today.
Magic Moon wrote,
The provencal Taro word does not include the meaning of a fool (stupid) but the lombardy word Tarous refers to a person who has a defect, which approaches fool and crazy
.
The Provencal "taro" means "defect" etc.; so when applied to a person, it would easily become "mentally defective," as confirmed by the French "tare" (accent acute on e). "Tarous" is also Provencale, merely an alternate for "taro"; according to one source "tarous" meant "fou," i.e. crazy, foolish, and in my third source "mentally defective."
In the rest of the post, I think in general you understand what I am saying, and we agree, at least in principle. Even if "tarus" does not mean "wood" in Latin, there is still "tarocch" meaning trunk of a tree or block of wood in Lombard, with a different derivation. See
viewtopic.php?p=23910#p23910 and following. (You acknowledge that, I think.) However, for that derivation, there is no explanation for how it became "tarau". For that reason, I prefer the "tarakh" derivation for "taroch" and "tarocco", which became "taro" in Provençal.
And I do not rule out a derivation of "tarau" from the Taro River, which surely did have that spelling then. If so, it would be derivative from "tarocco/tarocho," which would be prior and not explained by the river. However, even that role for the river and battle (accounting for "tarau") seems to me less likely than that through Provencal that I have proposed.