Absence of sound, as involving the French (7)
I believe the answer is:
silence
'absence of sound' is the definition.
(I've seen this before)
'as involving the french' is the wordplay.
'as' becomes 'since' (I've seen this before).
'involving' means one lot of letters goes inside another.
'the french' becomes 'le' ('the' in French).
'since' placed around 'le' is 'SILENCE'.
(Other definitions for silence that I've seen before include "There's nothing heard" , "Quietness" , "Soundlessness" , "What's left of burnt coal" , "Shut up!" .)