The last decade of a century (8)
I believe the answer is:
nineties
'the last decade of a century' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for nineties that I've seen before include "they were once described as naughty!" , "many old people are in" , "Previous decade" , "possibly last period of life" , "Last decade of century" .)