Left to fly around in the sun? (5)
I believe the answer is:
solar
'in the sun?' is the definition.
(solar means relating to the sun)
'left to fly around' is the wordplay.
'left' becomes 'l' (common abbreviation).
'to fly' becomes 'soar' (soaring is a kind of flying).
'around' means one lot of letters goes inside another.
'l' put into 'soar' is 'SOLAR'.
(Other definitions for solar that I've seen before include "room" , "Using the energy of the sun" , "chamber in old house" , "Concerning the sun" , "Relating to the sun" .)