What does 'corrupted' (world or society) mean?

Several people (several questions and answers) in [this topic](https://buddhism.stackexchange.com/q/24266/254) use the word "corrupted", especially applied to "the world" and "society". - What does the word "corrupted" mean? - Does it have a standard meaning in Buddhism, or is it idiosyncratic? Is it an objective (observable, shareable) property (of the world), or a subjective (personal) feeling? Do all schools (or yanas) define it the same way? Is it mentioned in any suttas? - Is it related to the idea that the Buddha's Dharma may (or will be, has been) lost, misinterpreted, over time? Or is it a different perception, applied to "society" rather than "dharma"? - Why would someone say that the world or society is becoming *more* corrupt? Compared to when and where, or what? Do schools (and/or teachers) differ in their view of whether the world is "progressing", i.e. whether it's improving or regressing?