Thankless person (7)
I believe the answer is:
ingrate
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">thankless person</span>' is the definition.<br/ ><span class="explanation-format__explanation">(someone who is ungrateful)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for ingrate that I've seen before include "Ungrateful person" , "Unthankful person" , "I'm not appreciative" , "without a word of thanks?" , "One not appreciating" .)