Good babies scintillate (7)
I believe the answer is:
glitter
'scintillate' is the definition.
(thesaurus)
'good babies' is the wordplay.
I cannot quite see how this works, but
'good' could be 'g' (abbreviation) and 'g' is found within the answer.
The remaining letters 'litter' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for glitter that I've seen before include "Shine brightly, coldly" , "Glisten, sparkle" , "Flashiness" , "Twinkle" , "Sparkly decoration" .)