feigning good feeling; putting on a cheerful front
Rare noun describing the act of pretending to be in a good mood or forcing a cheerful demeanor.
彼女の笑顔は作り機嫌だった。
Her smile was a forced cheerfulness.
Compound of 作り (つくり, 'making' or 'manufactured') and 機嫌 (きげん, 'mood' or 'humor'). The exact origin is uncertain, but it follows a pattern of similar compounds like 作り笑い (forced smile).