Rather fat (6)
(Other definitions for round that I've seen before include "stage of competition" , "Description of Tweedledum" , "rung of the ladder" , "Eighteen holes of golf" , "Item of music - single item of ammunition" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">rather fat</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 portly that I've seen before include "Rather fat" , "with corporation" , "Plump, corpulent" , "Stout and dignified" , "Rotund" .)