ふりをする details
Examples
pretend to; act as if — put on a deliberate front, knowing it doesn't match reality
声をかけられたのに、気づかないふりをしちゃった。
koe o kakerareta noni, kizukanai furi o shichatta.
Someone called out to me, but I pretended not to notice. casual
弟は宿題をやりたくなくて、寝たふりをしていた。
otouto wa shukudai o yaritakunakute, neta furi o shite ita.
My little brother didn't want to do his homework, so he pretended to be asleep. neutral
被告は事件について何も知らないふりをしていたが、証拠は違う事実を示していた。
hikoku wa jiken ni tsuite nani mo shiranai furi o shite ita ga, shouko wa chigau jijitsu o shimeshite ita.
The defendant acted as if he knew nothing about the incident, but the evidence pointed to a different truth. formal
具合が悪いふりして、学校休んだことあるよ。
guai ga warui furi shite, gakkou yasunda koto aru yo.
I've pretended to feel sick to skip school before, you know. casual
犯人は客のふりをして店に入ってきた。
hannin wa kyaku no furi o shite mise ni haitte kita.
The culprit posed as a customer and came into the store. neutral
Formation
plain clause + ふりをする（知らないふり・寝たふり・元気なふりをする など）attaches to plain clause{N}のふりをするattaches to noun
Notes
知らなかった), unlike the frozen っぽい/がち verb sets — plain-clause
covers the whole range, not a closed list.
Related patterns
Similar
Both render English "act like X," but みたいだ reports an honest outside impression of how something looks (具合[ぐあい]が悪[わる]いみたいだ "she looks unwell"), while 〜ふりをする names a deliberate performance the subject controls and knows is false (具合[ぐあい]が悪[わる]いふりをする "she's faking being unwell").