Cloudy: no blue about us (8)
I believe the answer is:
nebulous
'cloudy' is the definition.
(nebulous means cloudy or vague)
'no blue about us' is the wordplay.
'about' indicates an anagram.
'no'+'blue'='noblue'
'noblue' with letters rearranged gives 'nebulo'.
'nebulo'+'us'='NEBULOUS'
(Other definitions for nebulous that I've seen before include "Insubstantial, indistinct" , "Cloudy; hazy" , "Cloudlike; vague" , "Hazy and cloudlike" , "'Cloudy, lacking definite form (8)'" .)