Sensational piece of luck getting free (5)
I believe the answer is:
lurid
'sensational' is the definition.
(similar in meaning)
'piece of luck getting free' is the wordplay.
'piece of luck getting' becomes 'lu' (I am not sure about this - if you are sure you should believe this answer much more).
'free' becomes 'rid' (similar in meaning).
'lu'+'rid'='LURID'
Can you help me to learn more?
(Other definitions for lurid that I've seen before include "Fiery - sensational" , "Grim" , "In vivid detail" , "In shocking detail" , "Horrifying - sensational" .)