Crux and Nitty-gritty

Crux noun - The central part or aspect of something under consideration.

Nitty-gritty and crux are semantically related in most important part topic. In some cases you can use "Nitty-gritty" instead a noun "Crux".

Nitty-gritty noun - The specific practical details of something.

Crux and nitty-gritty are semantically related in basics topic. You can use "Crux" instead a noun phrase "Nitty-gritty".