They outrank viscounts
I believe the answer is:
earls
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">they outrank viscounts</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for earls that I've seen before include "London exhibition centre" , "Laser the British peers" , "Peers of the realm" , "Nobles" , "members of the House of Lords" .)