Despairing son overwhelmed by fate (4)
I believe the answer is:
lost
'despairing' is the definition.
Both the definition and answer are adjectives. Maybe you can see an association between them that I don't see?
'son overwhelmed by fate' is the wordplay.
'son' becomes 's' (genealogical abbreviation for son).
'overwhelmed by' is an insertion indicator (inserted letters get absorbed or overwhelmed).
'fate' becomes 'lot' (synonyms).
's' inserted into 'lot' is 'LOST'.
Can you help me to learn more?
(Other definitions for lost that I've seen before include "at sea" , "confused" , "Mislaid or was defeated" , "See 10" , "Missing" .)