Biodegrade cayenne pepper inside this! (5)
I believe the answer is:
decay
This clue might be a double definition.
'biodegrade' is the first definition.
(I know this)
'cayenne pepper inside this' is the second definition.
The definition suggests a singular noun which matches the answer.
Can you help me to learn more?
(Other definitions for decay that I've seen before include "Rot, perish" , "'Decompose, rot (5)'" , "Putrefy" , "Decompose or fall into ruin" , "Putrefaction" .)