Echo a little bit, penetrating rupture (7)
I believe the answer is:
resound
'echo' is the definition.
(synonyms)
'a little bit penetrating rupture' is the wordplay.
'a little bit' becomes 'sou' (informal term for a small amount of money).
'penetrating' means one lot of letters goes inside another.
'rupture' becomes 'rend' (rending is a kind of rupturing).
'sou' placed into 'rend' is 'RESOUND'.
(Other definitions for resound that I've seen before include "ring" , "Reverberate" , "Echo" .)