Plagiarist, imitator (7)
I believe the answer is:
copycat
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">plagiarist</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">imitator</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ ></span>
(Other definitions for copycat that I've seen before include "Emulator" , "One imitating another" , "Highly imitative" , "Done in imitation" , "Person (or crime) imitating another" .)