Loose, as a verb in english.
Among the myriad of uses for "loose" is its use as a verb.
In searching through the "usual suspects" in the verb form its uses are very limited and (in american english ) seem a bit archaic.
Examples from Oxford English and Macmillan:
They loosed a barrage of arrows against the oncoming infantry.
The recent uprisings have loosed a revolution in the region.
He loosed the dogs against the intruders.
Yes we have all seen this in literature,poetry and in some U.N speeches. but I cannot say that I have heard this in common ( but correct) speech.As language differs around our world, so then,
The questions are:
Do you use this form? do you hear it used ? How do you use it? Where are you in the world?
***Thank you all for your input
18 Answers
Most of the time I see "loose" as a verb, it's just a misspelling of "lose" 
I would agree with your summary of the word "loose" in verb form. However, I would say that using the word "let" in front of "loose" is more commonplace.
He let loose his arrow.
He let loose the dogs.
I am from multiple places along the East coast of the USA.
I never use loose in that way; I would always use unleash instead.
Apparently loosed can also be used in a different sense where I would always say loosened.
It is used where I am from (USA), however I don't commonly use it like in your examples.
If I was going to use it with the dog example, I'd say "He let the dogs loose on the invaders", "he loosed the dogs" sounds weird and incorrect to me.
I have heard it used as, " They set him loose" or maybe , let the horses loose. I don't think I hear it very much though,
Do you use this form? Me personally? No but I understand it perfectly
do you hear it used ? Only on the news etc
How do you use it? N/A
Where are you in the world? England
"They loosed a barrage of arrows against the oncoming infantry."
Yes, it's more of a "set expression" as I see it
They set him loose" or maybe , let the
horses loose.
Hey, but this is not a verb!!
Loose is an adjective. to lose a verb. and loosed...omg, I would KILL my students if they made that mistake
This is what I first thought, until I found this of course:
v. loosed, loos·ing, loos·es
v.tr.
To let loose; release: loosed the dogs.
To make loose; undo: loosed his belt.2.
Wow, interesting, I had no idea one could use loose as a verb.
I think loosed is one of those words like behemoth.
I agree 'loosed' as a past tense is archaic. I have seen it in literature but it is not a term i would use.
As others have said it would be expressed as 'let loose' . In Lectors example above I would say 'He let loose a stream of invective'
You can try a dictionary - loose is a legitimate verb, but refers to words; "he loosed a stream of invective". It has been used to mean "set free" but when does any of use ever actually set anything free? You can loose your dog, but only if you mean to imply that you are setting completely at liberty to run away, attack or run down something. Usually when you loose your dog, you are not actually loosing it because you will be (or should still be) in some control of the pooch. And originally, loose was just an adjective, but you know how we speakers of English are - If it isn't loose, let's loose it or at least loosen it! We can't resist using old words in new ways!
When you "let loose" (i.e., free, release from bonds) you are "allowing" the direct object to go "loose" which is an adjective (loose dog). Loosen is also a verb, and I bet everyone of us has loosened our shoes, belts, grip, etc. at one time or another.
I (and my family) like to speak this kind of English: "thrice" and "loosed" etc. My friends think it's pompous. 
"to loose" is a normal verb - as is "to loosen"
I have never heard or read 'loosed' being used in any of the ways you mentioned. In fact, 'loosed' just sounds completely wrong. I am from England.
I would say: "They fired a barrage of arrows against the oncoming infantry"
"The recent uprisings have led to a revolution in the region"
"He let loose the dogs against the intruders".
However, I must add I couldnt be 100% sure that the above are grammatically correct, I am just writing as I would speak!
I can't say that I have heard this form, but then, my experience of the world is very limited. 
I think in the third instance you've pointed out: 'He loosed the dogs against the intruders', I'd use the word, 'set'.
Although I wouldn't use 'set' in all the sentences in which you've used 'loosed'.
I think it's a very odd word...
I used it just yesterday! I was telling a story about a scene I'd observed in a store and I said, "And then she loosed a stream of obscenities on the salesclerk." But I wouldn't say it's a very common usage these days.
