LX (5)
I believe the answer is:
sixty
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">lx</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for sixty that I've seen before include "LX -- highest possible score with one dart" , "Threescore" , "Roman LX" , "Many more than nine" , "As many as four rugby teams" .)