Collapse, having sired terrible twins (9)
I believe the answer is:
disrepair
'collapse' is the definition.
(thesaurus)
'sired terrible twins' is the wordplay.
'terrible' is an anagram indicator.
'twins' becomes 'pair' (a pair of twins).
'sired' is an anagram of 'disre'.
'disre'+'pair'='DISREPAIR'
'having' acts as a link.
(Other definitions for disrepair that I've seen before include "poor state" , "Poor working order" , "rack and ruin" , "Neglected condition" , "Poor condition" .)