The last decade of a century (8)
I believe the answer is:
nineties
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">the last decade of a century</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(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" .)