Stop state visit, finally (5)
I believe the answer is:
avert
'stop' is the definition.
(to avert something is to stop or prevent it)
'state visit finally' is the wordplay.
'state' becomes 'aver' (both can mean to declare).
'finally' suggests the final letters.
The final letter of 'visit' is 't'.
'aver'+'t'='AVERT'
(Other definitions for avert that I've seen before include "Obviate" , "Parry" , "Head off" , "Prevent from occurring" , "Turn away or aside" .)