[miahwilde]

- "Vital" and "crucial" both indicate a required element.

- "Key" and "important" both indicate notable elements.

- "Key" can also be used to indicate a required element, i.e. "keystone", however it is not always used in this way.

- "Key" can also be used to indicate "there is only one" though it is not always used in this way.

When "key" is meant as "singular & required & notable" it probably carries the most weight of all these words. However, since it is not always used in that way, I personally tend to give it less weight.

In casual use I would order them like this (strongest to weakest): crucial, vital, key, important.

In formal use I would order them like this (strongest to weakest): key, vital, crucial, important.

My favorite thesaurus, ChatGPT, agrees with my casual use ranking. https://chat.openai.com/share/10bb8195-c7cd-4c0c-935f-f5b4c3...