The characters combine to literally mean “to pretend a manner and make an appearance.” The pairing of `模` and `样` creates the word `模样 (móyàng)`, which means “appearance” or “look.” Therefore, the idiom paints a picture of someone deliberately constructing a fake appearance and set of behaviors.
Chinese culture often values authenticity (真实, zhēnshí) and sincerity (诚恳, chéngkěn). `装模作样` is a direct critique of behavior that violates these values. It's seen as a form of insincerity that is often clumsy and transparent. While saving “face” (面子, miànzi) is important, doing so through an obvious, theatrical performance is looked down upon. A useful Western comparison is the phrase “to put on airs” or “to be theatrical.” However, `装模作样` is broader. “Putting on airs” usually implies feigning a higher social status. `装模作样` can apply to any kind of pretense—feigning sickness, pretending to be knowledgeable, acting innocent, or faking an emotion. The core of the Chinese term is the visible, often cringeworthy *performance* of the pretense itself. It suggests the person is not a very good actor, and their insincerity is showing.
`装模作样` is almost always used with a negative, critical, or mocking tone. It is versatile and can be found in daily conversation, literature, and online discussions.