Very bright ray bothered one (8)
I believe the answer is:
solitary
'one' is the definition.
(I've seen this before)
'very bright ray bothered' is the wordplay.
'very' becomes 'so' (both can mean 'extremely').
'bright' becomes 'lit' (similar in meaning).
'bothered' is an anagram indicator.
'ray' anagrammed gives 'ary'.
'so'+'lit'+'ary'='SOLITARY'
(Other definitions for solitary that I've seen before include "punishment" , "Lone; isolated" , "friendless" , "unique" , "Hermit living alone" .)