An alias, especially one adopted in order to deceive(noun)
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Use "assumed name" in a sentence
"She thereupon published a scandalous pamphlet under the title of “Florence Boyle Price, a Warning; by Speranza,” with the evident intention of causing the public to believe that the booklet was the composition of Lady Wilde under the assumed name of Florence Boyle Price."
"Later in life the generous and romantic prince diverted himself with the adventurous beneficence of Haroun al Raschid, visiting the poor in disguise, listening to the recital of their sufferings and wrongs, and relieving them with ready largesse of charity and justice; and nothing so pleased and flattered him as to be called, in his assumed name of Nak Pratt, “the wise,” to take part in their sports and fêtes."
"In 1676 Gabriel de Foigny, under the assumed name of Jacques Sadeur, published at Vannes a quaint little duodecimo volume, purporting to give a description of an unknown southern land."