Dispose of in haste (8)
I believe the answer is:
dispatch
I believe this is a double definition.
'dispose of' is the first definition.
(thesaurus)
'haste' is the second definition.
(thesaurus)
'in' acts as a link.
(Other definitions for dispatch that I've seen before include "Execute" , "Send promptly; murder" , "Post, perhaps" , "Take out" , "making killing" .)