expression, suru verb (irregular)
pretend; act as if
Used after a verb in the dictionary form or ta-form to mean pretending to do or have done something. Also used after nouns with の.
See also: 振り (ふり)
彼は寝たふりをした。
He pretended to be asleep.
知らないふりをしないでください
Please don't pretend you don't know.