不像话 is deeply rooted in Chinese cultural values that prioritize social harmony (和谐, héxié), order, and maintaining “face” (面子, miànzi). When an act is described as 不像话, it means it has disrupted this social order and likely caused someone (perhaps the speaker, the listener, or a third party) to lose face.
It's often used to enforce unwritten social rules, particularly regarding respect for elders, fairness in dealings, and public decorum. For example, a child publicly contradicting their parents or a business that blatantly cheats its customers would be classic examples of 不像话 behavior.
Comparison to Western Concepts: In English, we might say “That's outrageous,” “That's unacceptable,” or “How ridiculous!” While similar, 不像话 carries a stronger implication of violating a shared social standard. An English speaker might call a new fashion trend “ridiculous” based on personal taste. A Chinese speaker would use 不像话 to condemn an action that violates a collective sense of right and wrong, like an official abusing their power or a guest being incredibly rude to their host. The judgment is less about personal opinion and more about a breach of social contract.