Defensive vet to price order (10)
I believe the answer is:
protective
'defensive' is the definition.
('protective' can be similar in meaning to 'defensive')
'vet to price order' is the wordplay.
'order' is an anagram indicator.
'vet'+'to'+'price'='vettoprice'
'vettoprice' with letters rearranged gives 'PROTECTIVE'.
(Other definitions for protective that I've seen before include "Shielding" , "Serving to keep safe" .)