Having a sound source, it's tasteful (5)
I believe the answer is:
sauce
'having a sound source' is the definition.
I can't tell whether this definition defines the answer.
'it's tasteful' is the wordplay.
I cannot quite see how this works, but
'it' could be 'sa' (old-fashioned abbreviation for sex appeal) and 'sa' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for sauce that I've seen before include "Nerve" , "Gravy" , "Informal impudence or food flavouring" , "naughtiness" , "Moistener for food" .)