Confound, so a hint's in order (8)
I believe the answer is:
astonish
'confound' is the definition.
(thesaurus)
'so a hint's in order' is the wordplay.
'in order' indicates anagramming the letters (the letters in a new order).
'so'+'a'+'hints'='soahints'
'soahints' with letters rearranged gives 'ASTONISH'.
(Other definitions for astonish that I've seen before include "Confound" , "Startle" , "Shock with surprise" , "are staggering" , "'knock for six'?" .)