Fieldwork concerning question (7)
I believe the answer is:
redoubt
'fieldwork' is the definition.
(thesaurus)
'concerning question' is the wordplay.
'concerning' becomes 're'.
'question' becomes 'doubt' (doubting is a kind of questioning**).
're'+'doubt'='REDOUBT'
(Other definitions for redoubt that I've seen before include "fortress" , "Defensive fieldwork" , "Tube rod used in small fortification" , "Obtrude in kind of military fieldwork" , "Temporary military fortification" .)