It's wrong — it's wrong to be seized by force (7)
I believe the answer is:
mistake
'it's wrong' is the definition.
(a mistake is something wrong or incorrect)
'it's wrong to be seized by force' is the wordplay.
'wrong' indicates an anagram.
'to be seized by' is an insertion indicator.
'force' becomes 'make' (to make someone do something is to force them).
'its' anagrammed gives 'ist'.
'ist' going into 'make' is 'MISTAKE'.
(Other definitions for mistake that I've seen before include "Oversight" , "Fault" , "Wrong action or judgment" , "16 down" , "Slip" .)