Tedious, dreary (4)
I believe the answer is:
dull
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">tedious</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >'<span class="explanation-format__original">dreary</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ ></span>
(Other definitions for dull that I've seen before include "Drab" , "Lusterless or uninteresting" , "Boring - not sunny" , "Uninspiring" , "Matt; overcast" .)