Less clear, fade in drum beat (7)
I believe the answer is:
muddier
'less clear' is the definition.
(as in muddy water)
'fade in drum beat' is the wordplay.
'fade' becomes 'die' (fade can mean to die away).
'in' means one lot of letters goes inside another.
'beat' indicates an anagram.
'drum' is an anagram of 'mudr'.
'die' inserted into 'mudr' is 'MUDDIER'.
(Other definitions for muddier that I've seen before include "More obscure" , "Less clear" , "More confused" .)