Tense gent hit out (7)
I believe the answer is:
tighten
'tense' is the definition.
(I've seen this before)
'gent hit out' is the wordplay.
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'gent'+'hit'='genthit'
'genthit' with letters rearranged gives 'TIGHTEN'.
(Other definitions for tighten that I've seen before include "Make more taut" , "Give an extra turn" , "Apply increased tension or security" , "Make stricter" , "Restrict" .)