Some rights are not absolute in their nature, but still cannot be restricted in a way that takes away the essence of that right in any circumstances. 

Some human rights are considered very important. These rights can be referred to as rights that cannot be violated at their core. 

This essentially means that some elements of these rights can be restricted or their exercise regulated, however, they cannot be restricted in a way that their very essence is taken away. 

These rights are not expressly listed in human rights instruments. Their recognition as rights that cannot be restricted at their core, usually comes from the case-law of a court or expert body created under a specific human rights instrument. These courts or expert bodies interpret the rights to supervise how states are fulfilling their obligations and the nature of rights is often developed and explained in their decisions. 

example The right to a fair trial is a right that must always be upheld in its core. It cannot be restricted in a way that takes away its essence - restrictions cannot render a trial unfair. However, many aspects of this right can be restricted by, for example, setting time limits for court submissions or legal criteria for appeals.

Human Rights Guide

A European platform for human rights education