Bad lighting appears only in an episode (5)
I believe the answer is:
arson
'bad lighting' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Maybe you can see a link between them that I can't see?
'appears only in an episode' is the wordplay.
'ARSON' is hidden in amongst the letters.
But, I am unsure how the hidden word is indicated.
Can you help me to learn more?
(Other definitions for arson that I've seen before include "Fire-raiser's crime" , "It may get you in court" , "serious offence" , "Felonious burning of property" , "A burning crime" .)