Dry, quiet and mischievous (5)
I believe the answer is:
Here is my best explanation:
'dry' is the definition.
(parching is a kind of drying)
'quiet and mischievous' is the wordplay.
'quiet' becomes 'p' (music symbol for 'piano').
'and' is a charade indicator (letters next to each other).
'mischievous' becomes 'arch' (I've seen this before).
(Other definitions for parch that I've seen before include "Scorch", "Dehydrate", "Cause to wither", "Get overheated", "Cut off water supply", "Make hot and dry", "Make dry through heat" and "Dry out with heat".)