Sparkling son has to wait (6)
I believe the answer is:
starry
'sparkling' is the definition.
(similar in meaning)
'son has to wait' is the wordplay.
'son' becomes 's' (genealogical abbreviation for son).
'has' is a charade indicator (letters next to each other).
'to wait' becomes 'tarry' (to tarry is to wait or linger).
's'+'tarry'='STARRY'
(Other definitions for starry that I've seen before include "Like the optimist's eyes or the sky at night" , "after dark, it's clear" , "like Hollywood Boulevard?" , "Like a clear night sky" , "'Of cloudless climes and - - skies' (Byron)" .)