Encumbrance (6)
I believe the answer is:
burden
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">encumbrance</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for burden that I've seen before include "Main theme (of book)" , "Load or responsibility carried" , "A heavy load or difficulty" , "Weigh down - load" , "Oppressive duty" .)