Extremely pitiable hush, in which thousands at first — die of this? (10)
I believe the answer is:
pestilence
'die of this?' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'extremely pitiable hush in which thousands at first' is the wordplay.
'extremely' says to hollow out the word (remove centre letters) (only the extremes of the word are used).
'hush' becomes 'silence' (synonyms).
'in which' is an insertion indicator.
'at first' says to take the initial letters.
'pitiable' with its centre taken out is 'pe'.
The initial letter of 'thousands' is 't'.
'silence' enclosing 't' is 'stilence'.
'pe'+'stilence'='PESTILENCE'
Can you help me to learn more?
(Other definitions for pestilence that I've seen before include "dire horseman?" , "Deadly epidemic disease" , "Fatal epidemic disease" , "it's an agent of evil" , "that'll plague you" .)