Lad accepting kiss with an indifferent sound? (4)
I believe the answer is:
boxy
'with an indifferent sound?' is the definition.
('boxy' refers to low-quality audio)
'lad accepting kiss' is the wordplay.
'lad' becomes 'boy' (I've seen this before).
'accepting' means one lot of letters goes inside another.
'kiss' becomes 'x'.
'boy' placed around 'x' is 'BOXY'.
(Other definitions for boxy that I've seen before include "Having a square appearance" , "Squarish in shape" .)