I am looking for clues on the obscure etymology of the (otherwise rather common) Romanian expression Valea!, a imperative mood formula meaning "Go away", "Be gone" or "Beat it".
Romanian has no authoritative and complete etymological dictionary at the moment. Those in existence are either partially outdated, incomplete, or dubious personal contributions. Anyway, I was not able to find an entry on this term in any etymological dictionary, but I have found a source that mentions it as a slang (argot) term, which it most certainly is not. It is a popular, rural, regional expression (from southern Romania), that may have entered urban slang in regions where it was otherwise absent, but it is not a recent creation of the slang language.
In such obscure cases of Romanian etymology, looking for Italian clues is always a good idea. (For example, in this way I was able to find that the Romanian word pitic = "dwarf(ish)" is of Latin origin, unlike what some dictionaries claimed, as said here, because similar forms can be found in the Italian area - cf. Milanese: pitinu, Sardinian: pithinnu, piticu, piticheddu.)
At first view, Valea! looks like the Romanian noun vale ("valley", Italian valle) with the feminine postfixed definite article a (and I guess that's how it is seen by the dictionary that considers it a slang formation), but it is much closer both semantically and close enough morphologically to the Italian imperative mood Vai!, with the same meaning, of which I read here that it might come from vādō, vadere (unlike andare), from where descend Italian guado and Romanian vad (shallow, ford).
The origin of the common Romanian word for to go (merge) is different, but Romanian future tense of verbs is build with auxiliary forms probably based on vādō, vadere, a root which is also reflected in another regional imperative expression (but much more rarely used), va! ("go!"), and in the formula mai va, literally "still goes", but meaning "it will take some more time".
My intuition is that the etymology of Valea! should be considered in relation to that of the Italian Vai! and Va! (go away, go).
But what about that L? Is there some regional Italian language or dialect that has a parallel form including a L?
I am asking this because I want to look at alternative possibilities—the other one being that Valea! is just the reduced imperative form of a verbal (composite) expression including the noun vale (valley): there are such expressions in Romanian, the best candidate being a-și lua valea, literally "take one's valley", meaning "to go away", much like in the French form aller à vau-l’eau - "to go downhill, to go down the drain, to go awry", but where the verb "to go" is a lua (from Latin levāre, “to lift”, cf. Italian levare), normally meaning "to take", but also meaning "to go" when coupled with "road", "path" (a lua calea="to take the path", cf. Italian prendere la strada, French prendre la route etc). - Therefore, in this case valley=vale just means path/road (namely that defined by a water course, or a downhill path).
In relation to this alternative explanation, the question would be: is there a case in Italian where a verbal form meaning "to go" or "go away" is coupled with or includes the noun valle (valley)?