Diss (6)
I believe the answer is:
insult
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">diss</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that diss can be written as insult)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for insult that I've seen before include "Demeaning remark" , "Cause offence to" , "Treat with abuse" , "Treat disrespectfully" , "Hurtful and offensive remark" .)