Severe trial (6)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">severe trial</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for ordeal that I've seen before include "Tough test in Laredo" , "Long, unpleasant experience" , "Struggle" , "A difficult or harrowing time" , "Torment" .)
(Another definition for acidtest that I've seen is " It might provide proof".)