Journalist finally writes about dishonest person (7)
I believe the answer is:
twister
'dishonest person' is the definition.
(I've seen this before)
'journalist finally writes about' is the wordplay.
'finally' indicates one should take the final letters.
'about' indicates an anagram.
The final letter of 'journalist' is 't'.
'writes' is an anagram of 'wister'.
't'+'wister'='TWISTER'
(Other definitions for twister that I've seen before include "One-eyed menace" , "Tornado (American)" , "Dishonest person" , "'sixties dancer?" , "Funnel-shaped wind" .)