> On the other hand, Isaiah 19:7 has the same spelling not in the
possessive use
According to the traditional vocalization, this is not ervat but arot,
i.e. the plural of some unknown word, probably meaning moss.
> ... Habakkuk 3:13 is more problematic.
Once again here it is vocalized arot, but the meaning is clearly
the infinitive of "to destroy" as in (RU of Psalms 137.
> In other words, you are suggesting that this is more of an idiomatic
> use instead of according to strict dictionary meaning. That makes
sense.
I think it is a natural extension of the meaning (what is called in
Hebrew "behashala").
> That could be more than just fortifications, e.g. the land could have
> been depopulated from disease so that the fortifications could not be
manned, or other "bareness",
> i.e. weakness, that would induce an enemy to attack.