Less heavy (7)
I believe the answer is:
lighter
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">less heavy</span>' is the definition.<br/ ><span class="explanation-format__explanation">('light' can be the opposite of 'heavy' so perhaps 'lighter' is reasonable for 'less heavy')</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for lighter that I've seen before include "Kind of barge - carrying less?" , "Barge; flame producer" , "The girl (anag.)" , "carrying less cargo?" , "Cargo barge; smoker's accessory" .)