A waste of time, to be blunt? (9)
I believe the answer is:
pointless
I believe this is a double definition.
'a waste of time' is the first definition.
(something pointless is a waste of time)
'be blunt?' is the second definition.
('pointless' can be similar in meaning to 'blunt')
'to' acts as a link.
(Other definitions for pointless that I've seen before include "Serving no purpose" , "missing a target" , "Ineffectual" , "Like a blunt arrow" , "having scored zero" .)