Poorly insured son is going bankrupt (6)
I believe the answer is:
ruined
'bankrupt' is the definition.
(I've seen this in another clue)
'poorly insured son is going' is the wordplay.
'poorly' indicates an anagram (a poor spelling).
'son' becomes 's' (genealogical abbreviation for son).
'is going' is a deletion indicator.
'insured' with 's' taken away is 'inured'.
'inured' is an anagram of 'RUINED'.
(Other definitions for ruined that I've seen before include "Irreparably damaged" , "shot" , "Wrecked" , "Broke" , "Spoilt" .)