Brilliant silver-blue combo? (5)
I believe the answer is:
aglow
'brilliant' is the definition.
'silver-blue combo?' is the wordplay.
'silver' becomes 'ag' (Ag is the chemical symbol for silver).
'blue' becomes 'low' (I've seen this in other clues).
'combo?' means one lot of letters go next to another.
'ag'+'low'='AGLOW'
(Other definitions for aglow that I've seen before include "Shining" , "Softly bright or radiant" , "On fire" , "Smouldering" , "Gleaming" .)