From the sun, thus a bit glaring (5)
I believe the answer is:
solar
'from the sun' is the definition.
(solar means relating to the sun)
'thus a bit glaring' is the wordplay.
I cannot really see how this works, but
'thus' could be 'so' (synonyms) and 'so' is present in the answer.
'a' is within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for solar that I've seen before include "Using the energy of the sun" , "Pertaining to the sun" , "Sun-powered" , "of heavenly body" , "like a star" .)