Dear PG Dave,
you asked about upaayaasa.
Meanwhile there was some correspondance, and since I could not follow
it, I may repeat what you got already. Then just leave it.
I found in the Co. to the Vibhanga (Second Book of Abhidhamma), the
Sammoha vinodanii (Dispeller of Delusion Ch IV, 106 ):<Woe.
In the exposition of woe, aayaaso (trouble) is in the sense of being
troubled; this is a name for mental weariness which occurs in the act
of sinking and foundering. Upaayaaso [100.22] (woe) is great trouble.
Aayaasitatta.m (troubledness) is the state of being troubled.
Upaayaasitatta.m (woefulness) is the state of being woeful.
Aya.m vuccati upaayaaso (this is called woe): it is this woe that is
being spoken of here. It has the characteristic of frustration. Its
nature is moaning. It is manifested as dejection.>
It is then explained that it is the basis for bodily and mental
suffering. There is a verse:
<Because with burning of the mind
likewise with bodily dejection too.
Woe produces such great suffering,
it is itself, therefore, called suffering.>