Curve where car crashed by husband (4)
I believe the answer is:
arch
'curve' is the definition.
(synonyms)
'car crashed by husband' is the wordplay.
'crashed' is an anagram indicator.
'by' is a charade indicator (letters next to each other).
'husband' becomes 'h' ().
'car' anagrammed gives 'arc'.
'arc'+'h'='ARCH'
'where' is the link.
(Other definitions for arch that I've seen before include "Cunning; span" , "Curved spanning structure" , "Instep of foot" , "architectural feature" , "in short, is out of date" .)