Uneasy over Sun being playful? (7)
I believe the answer is:
nervous
'uneasy' is the definition.
(I know that uneasy can be written as nervous)
'over sun being playful?' is the wordplay.
'being playful?' indicates anagramming the letters (I've seen 'playful' mean this).
'over'+'sun'='oversun'
'oversun' with letters rearranged gives 'NERVOUS'.
(Other definitions for nervous that I've seen before include "Highly-strung" , "Anxious, uneasy" , "Agitated and apprehensive" , "Easily agitated, timid" , "Jumpy" .)