Gnarled (6)
I believe the answer is:
knotty
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">gnarled</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that gnarled can be written as knotty)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for knotty that I've seen before include "Tangled - snarled" , "Tree trunk with hard masses - it's problematic" , "Convoluted" , "Difficult to unravel" , "Full of tangles; extremely intricate" .)