Star embarrassed about part (6)
I believe the answer is:
sunder
'part' is the definition.
(I've seen this before)
'star embarrassed about' is the wordplay.
'star' becomes 'sun' (the Sun is a star).
'embarrassed' becomes 'red' (someone may blush or go red when embarrassed).
'about' says the letters should be written backwards.
'red' written backwards gives 'der'.
'sun'+'der'='SUNDER'
(Other definitions for sunder that I've seen before include "Nursed so as to tear apart" , "Break or tear apart, maybe a relationship" , "Split apart" , "Separate the odd red sun" , "Red sun could part" .)