Infinite time (8)
I believe the answer is:
eternity
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">infinite time</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 eternity that I've seen before include "life everlasting" , "That's a very long time" , "World without end" , "Unending time" , "Perpetuity" .)