Money covering up steps to produce plague (10)
I believe the answer is:
pestilence
'plague' is the definition.
(synonyms)
'money covering up steps' is the wordplay.
'money' becomes 'pence' (I've seen this before).
'covering up' indicates putting letters inside.
'steps' becomes 'stile' (I've seen this in other clues).
'pence' going around 'stile' is 'PESTILENCE'.
'to produce' is the link.
(Other definitions for pestilence that I've seen before include "dire horseman?" , "morally harmful influence" , "Deadly epidemic disease" , "that'll plague you" , "it's an agent of evil" .)