vicious (circle|cycle)

Plural

vicious circles

a situation where one problem brings about another and that only worsens the original problem

The idiom "vicious circle" is used to refer to a self-perpetuating or self-reinforcing sequence of events or situations where one problem leads to another, and these issues continue to worsen each other in an unending loop. Its origin is related to the idea of a circle with harmful qualities, where each part of the circle reinforces the negative impact of the others.

His chronic procrastination created a vicious circle, as missed deadlines led to stress, and stress further hindered his ability to meet deadlines.
The company's financial troubles resulted in layoffs, which, in turn, led to a decreased workforce, creating a vicious cycle of reduced productivity and more financial woes.
In unhealthy relationships, a lack of trust and communication can contribute to a vicious circle of misunderstandings and conflict.
For those struggling with addiction, breaking the vicious circle of substance abuse often requires professional intervention and support.
The vicious circle of poverty can be challenging to escape, as financial hardships can lead to limited opportunities and vice versa.

an argument in which the conclusion is assumed in the premise, resulting in circular reasoning

Claiming "the law is just because it is the law" is a classic vicious circle.
The debate fell into a vicious cycle when each side used its own claim as proof.
Saying "I am right because I say so" is an example of a vicious circle.
His reasoning was a vicious circle, assuming the very point under dispute.
Accusing someone of dishonesty based on the assumption that they lie is a vicious cycle.