Sally of a kind, that is (6)
I believe the answer is:
sortie
'sally' is the definition.
(I know that sally can be written as sortie)
'kind that is' is the wordplay.
'kind' becomes 'sort' (synonyms).
'that is' becomes 'ie' (short for Latin 'id est', 'that is').
'sort'+'ie'='SORTIE'
'of a' is the link.
(Other definitions for sortie that I've seen before include "Military manoeuvre" , "Attack by a besieged garrison" , "Sally" , "Military aircraft flight" , "Short foray" .)