Pen name or pseudonym (3,2,5)
I believe the answer is:
nom de plume
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">pen name</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >'<span class="explanation-format__original">pseudonym</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(nom de plume is a kind of pseudonym)</span><br/ ><br/ ></span>
(Other definitions for nom de plume that I've seen before include "Assumed name" , "Pen-name" , "False name" , "Author's pseudonym" , "Pen name" .)