Cold-hearted (6)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">cold-hearted</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for unkind that I've seen before include "Hardhearted" , "Uncaring, nasty" , "Thoughtless -- inhumane" , "Unsympathetic or cruel" , "Not gentle or considerate" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">cold-hearted</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for callous that I've seen before include "Hard-hearted" , "Emotionally hardened" , "Cruel or unsympathetic" , "Not feeling" , "Insensitive, cruel" .)