I moan about a biblical character (5)
I believe the answer is:
naomi
'a biblical character' is the definition.
(I've seen this before)
'i moan about' is the wordplay.
'about' says the letters should be written in reverse.
'i'+'moan'='imoan'
'imoan' in reverse letter order is 'NAOMI'.
(Other definitions for naomi that I've seen before include "Girl's name -- I moan (anag)" , "Ruth's mother-in-law (Old Testament)" , "woman's name" , "Girl" , "Girl's name, meaning "pleasant"" .)