Assumption of a false identity (9)
I believe the answer is:
imposture
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">assumption of a false identity</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for imposture that I've seen before include "Pretending to be another person" , "The assuming of a false identity" , "Trick" , "deception" , "Fraud" .)