Not level or smooth (6)
I believe the answer is:
uneven
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">not level or smooth</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for uneven that I've seen before include "Inconsistant in quality" , "Odd - rough" , "Rough on the surface" , "Not uniform or smooth" , "Bumpy - odd" .)