Another Croesus with concerning wealth (9)
I believe the answer is:
resources
'wealth' is the definition.
(thesaurus)
'another croesus with concerning' is the wordplay.
'another' is an anagram indicator.
'with' says to put letters next to each other.
'concerning' becomes 're' (both can mean on a particular topic).
'croesus' is an anagram of 'sources'.
'sources' put after 're' is 'RESOURCES'.
(Other definitions for resources that I've seen before include "Teaching materials" , "Personal attributes" , "Useful materials, assets" , "funds" , "Available reserve supplies" .)