Dull or tactless (5)
I believe the answer is:
blunt
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">dull</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that dull can be written as blunt)</span><br/ ><br/ >'<span class="explanation-format__original">tactless</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ ></span>
(Other definitions for blunt that I've seen before include "Lacking edge; forthright" , "Brusque" , "Candid" , "Frank and forthright" , "6 [JOHNSON]" .)