Originally a Buddhist term for the inevitable results of past actions; in modern usage, it often describes a person who is cold-hearted or ruthless, implying that their cruelty will bring karmic consequences.
If you do such cruel things, it will come back to you someday.
From Buddhist terminology, combining 因 (cause) and 業 (action/karma), referring to the results of actions in previous lives. The modern sense of 'heartless' likely developed from the idea that cruel actions will lead to karmic retribution.
