Oddly, does rhythm lead to corruption? (9)
I believe the answer is:
decadence
'corruption?' is the definition.
(I've seen this before)
'oddly does rhythm' is the wordplay.
'oddly' means one should take alternating letters (letters in the odd-numbered positions are used).
'rhythm' becomes 'cadence' (cadence is a kind of rhythm).
The alternate letters of 'does' are 'de'.
'de'+'cadence'='DECADENCE'
'lead to' acts as a link.
(Other definitions for decadence that I've seen before include "depravity" , "Immoral behaviour" , "Perishing state" , "Debauchery, degeneracy" , "Moral or cultural decline" .)