Reject bluntly (6)
I believe the answer is:
rebuff
'reject bluntly' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for rebuff that I've seen before include "Snub or contemptuous refusal" , "Reject in an ungrateful manner" , "Blunt rejection" , "Turn off" , "Deliberate discourteous act" .)