Uncontroversial (4)
I believe the answer is:
safe
'uncontroversial' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for safe that I've seen before include "Metal box for security" , "Container that may be cracked?" , "Metal box for storing valuables in" , "Reliable" , "Cash-box" .)