Insipid, lifeless (5)
I believe the answer is:
vapid
I believe this is a double definition.
'insipid' is the first definition.
(I know that insipid can be written as vapid)
'lifeless' is the second definition.
(I've seen this in another clue)
(Other definitions for vapid that I've seen before include "Offering no stimulation" , "Dull, insipid, flat" , "Dull and tasteless" , "Wishy-washy" , "Boring, flat" .)