Wives have one party for dowager (5)
I believe the answer is:
widow
'dowager' is the definition.
(I've seen this before)
'wives have one party' is the wordplay.
'wives' becomes 'ww' (an abbreviation for wife written twice).
'have' is an insertion indicator.
'one' becomes 'I' (Roman numeral).
'party' becomes 'do' (do is a kind of party).
'i'+'do'='ido'
'ww' enclosing 'ido' is 'WIDOW'.
'for' is the link.
(Other definitions for widow that I've seen before include "The Merry --, operetta" , "See 20" , "One without partner" , "Black -----, cannibalistic venomous spider" , "eg Dowager" .)