Contemplates Mirror and Sun (8)
I believe the answer is:
reflects
'contemplates' is the definition.
('reflect' can be a synonym of 'contemplate')
'mirror and sun' is the wordplay.
'mirror' becomes 'reflect' (mirror can mean to reflect).
'and' is a charade indicator (letters next to each other).
'sun' becomes 'S' (abbreviation).
'reflect'+'s'='REFLECTS'
(Other definitions for reflects that I've seen before include "Throws back an image" , "Mirrors or ponders" , "Thinks deeply like mirror?" , "Looks back" , "'Contemplates, considers (8)'" .)