Most unsightly (7)
I believe the answer is:
ugliest
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">most unsightly</span>' is the definition.<br/ ><span class="explanation-format__explanation">('ugly' can be similar in meaning to 'unsightly')</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ugliest that I've seen before include "Least pretty" , "superlatively unattractive" , "Most deficient in beauty" , "Most unattractive in appearance" , "Least attractive" .)