Conclude with refusal: hell! (7)
I believe the answer is:
inferno
'hell' is the definition.
(inferno can mean hell as in Dante's Inferno)
'conclude with refusal' is the wordplay.
'conclude' becomes 'infer' (inferring is a kind of concluding).
'with' says to put letters next to each other.
'refusal' becomes 'no' (it's a no).
'infer'+'no'='INFERNO'
(Other definitions for inferno that I've seen before include "A raging fire as in hell - ask Dante" , "Big fire" , "Huge fire" , "Terrible fire" , "hot spot" .)