Senator's back, stopping terribly austere Republican official managing funds (9)
I believe the answer is:
treasurer
'official managing funds' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'senator's back stopping terribly austere republican' is the wordplay.
'back' says to take the final letters (the letter at the back).
'stopping' indicates putting letters inside (inserted letters stop or plug a gap).
'terribly' is an anagram indicator.
'republican' becomes 'R' (political abbreviation).
The final letter of 'senator' is 'r'.
'austere'+'r'='austerer'
'austerer' with letters rearranged gives 'treasuer'.
'r' put into 'treasuer' is 'TREASURER'.
Can you help me to learn more?
(Other definitions for treasurer that I've seen before include "Financial controller" , "Society official" , "Committee member" , "One who highly prizes" , "Person holding purse" .)