Banter that's not lasted well? (8)
I believe the answer is:
badinage
This clue is a double definition.
'banter' is the first definition.
(badinage is a kind of banter)
'not lasted well?' is the second definition.
(bad (not well) at lasting (in age))
'that's' is the link.
(Other definitions for badinage that I've seen before include "Humorous, witty conversation" , "Teasing talk, banter" , "bit of playful repartee" , "joking" , "Humorous banter" .)