Less common (5)
I believe the answer is:
rarer
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">less common</span>' is the definition.<br/ ><span class="explanation-format__explanation">('rare' can be the opposite of 'common' so perhaps 'rarer' is reasonable for 'less common')</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for rarer that I've seen before include "More unusual" , "steak may be wanted thus?" , "More scarce or uncommon" , "Comparatively sparse" , "(Of meat) less cooked" .)