Nothing rich about this group of singers (5)
I believe the answer is:
choir
'this group of singers' is the definition.
(a choir is a singing group)
'nothing rich about' is the wordplay.
'nothing' becomes 'O' (O resembles 0).
'about' indicates an anagram.
'o'+'rich'='orich'
'orich' is an anagram of 'CHOIR'.
(Other definitions for choir that I've seen before include "They sing" , "Religious singers" , "Group of singers, often in church" , "Carol singers?" , "Body of singers" .)