Level, not bumpy (4)
I believe the answer is:
even
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">level</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that level can be written as even)</span><br/ ><br/ >'<span class="explanation-format__original">not bumpy</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for even that I've seen before include "Equable" , "Level, equal" , "Level, par" , "Stable" , "Unvarying" .)