An assumed name (5)
I believe the answer is:
alias
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">an assumed name</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for alias that I've seen before include "Otherwise - an assumed name" , "Alternative name" , "Otherwise known as" , "Assumed identity" , "aka" .)