That Rene can be menace (8)
I believe the answer is:
threaten
'menace' is the definition.
(I know that menace can be written as threaten)
'that rene can be' is the wordplay.
'can be' indicates anagramming the letters.
'that'+'rene'='thatrene'
'thatrene' is an anagram of 'THREATEN'.
(Other definitions for threaten that I've seen before include "Put in jeopardy" , "Foreshadow" , "Bully" , "Utter intentions of injury or punishment" , "Put at risk, endanger" .)