Become wearisome (4)
I believe the answer is:
pall
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">become wearisome</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for pall that I've seen before include "Become less appealing" , "A dark cover; cease to interest" , "Become wearisome" , "tedious here" , "Cloth over a coffin - become insipid" .)